xref: /freebsd/contrib/llvm-project/clang/lib/CodeGen/CGStmt.cpp (revision c80e69b00d976a5a3b3e84527f270fa7e72a8205)
1 //===--- CGStmt.cpp - Emit LLVM Code from Statements ----------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This contains code to emit Stmt nodes as LLVM code.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "CGDebugInfo.h"
14 #include "CGOpenMPRuntime.h"
15 #include "CodeGenFunction.h"
16 #include "CodeGenModule.h"
17 #include "TargetInfo.h"
18 #include "clang/AST/Attr.h"
19 #include "clang/AST/Expr.h"
20 #include "clang/AST/Stmt.h"
21 #include "clang/AST/StmtVisitor.h"
22 #include "clang/Basic/Builtins.h"
23 #include "clang/Basic/DiagnosticSema.h"
24 #include "clang/Basic/PrettyStackTrace.h"
25 #include "clang/Basic/SourceManager.h"
26 #include "clang/Basic/TargetInfo.h"
27 #include "llvm/ADT/ArrayRef.h"
28 #include "llvm/ADT/DenseMap.h"
29 #include "llvm/ADT/SmallSet.h"
30 #include "llvm/ADT/StringExtras.h"
31 #include "llvm/IR/Assumptions.h"
32 #include "llvm/IR/DataLayout.h"
33 #include "llvm/IR/InlineAsm.h"
34 #include "llvm/IR/Intrinsics.h"
35 #include "llvm/IR/MDBuilder.h"
36 #include "llvm/Support/SaveAndRestore.h"
37 #include <optional>
38 
39 using namespace clang;
40 using namespace CodeGen;
41 
42 //===----------------------------------------------------------------------===//
43 //                              Statement Emission
44 //===----------------------------------------------------------------------===//
45 
46 namespace llvm {
47 extern cl::opt<bool> EnableSingleByteCoverage;
48 } // namespace llvm
49 
EmitStopPoint(const Stmt * S)50 void CodeGenFunction::EmitStopPoint(const Stmt *S) {
51   if (CGDebugInfo *DI = getDebugInfo()) {
52     SourceLocation Loc;
53     Loc = S->getBeginLoc();
54     DI->EmitLocation(Builder, Loc);
55 
56     LastStopPoint = Loc;
57   }
58 }
59 
EmitStmt(const Stmt * S,ArrayRef<const Attr * > Attrs)60 void CodeGenFunction::EmitStmt(const Stmt *S, ArrayRef<const Attr *> Attrs) {
61   assert(S && "Null statement?");
62   PGO.setCurrentStmt(S);
63 
64   // These statements have their own debug info handling.
65   if (EmitSimpleStmt(S, Attrs))
66     return;
67 
68   // Check if we are generating unreachable code.
69   if (!HaveInsertPoint()) {
70     // If so, and the statement doesn't contain a label, then we do not need to
71     // generate actual code. This is safe because (1) the current point is
72     // unreachable, so we don't need to execute the code, and (2) we've already
73     // handled the statements which update internal data structures (like the
74     // local variable map) which could be used by subsequent statements.
75     if (!ContainsLabel(S)) {
76       // Verify that any decl statements were handled as simple, they may be in
77       // scope of subsequent reachable statements.
78       assert(!isa<DeclStmt>(*S) && "Unexpected DeclStmt!");
79       return;
80     }
81 
82     // Otherwise, make a new block to hold the code.
83     EnsureInsertPoint();
84   }
85 
86   // Generate a stoppoint if we are emitting debug info.
87   EmitStopPoint(S);
88 
89   // Ignore all OpenMP directives except for simd if OpenMP with Simd is
90   // enabled.
91   if (getLangOpts().OpenMP && getLangOpts().OpenMPSimd) {
92     if (const auto *D = dyn_cast<OMPExecutableDirective>(S)) {
93       EmitSimpleOMPExecutableDirective(*D);
94       return;
95     }
96   }
97 
98   switch (S->getStmtClass()) {
99   case Stmt::NoStmtClass:
100   case Stmt::CXXCatchStmtClass:
101   case Stmt::SEHExceptStmtClass:
102   case Stmt::SEHFinallyStmtClass:
103   case Stmt::MSDependentExistsStmtClass:
104     llvm_unreachable("invalid statement class to emit generically");
105   case Stmt::NullStmtClass:
106   case Stmt::CompoundStmtClass:
107   case Stmt::DeclStmtClass:
108   case Stmt::LabelStmtClass:
109   case Stmt::AttributedStmtClass:
110   case Stmt::GotoStmtClass:
111   case Stmt::BreakStmtClass:
112   case Stmt::ContinueStmtClass:
113   case Stmt::DefaultStmtClass:
114   case Stmt::CaseStmtClass:
115   case Stmt::SEHLeaveStmtClass:
116     llvm_unreachable("should have emitted these statements as simple");
117 
118 #define STMT(Type, Base)
119 #define ABSTRACT_STMT(Op)
120 #define EXPR(Type, Base) \
121   case Stmt::Type##Class:
122 #include "clang/AST/StmtNodes.inc"
123   {
124     // Remember the block we came in on.
125     llvm::BasicBlock *incoming = Builder.GetInsertBlock();
126     assert(incoming && "expression emission must have an insertion point");
127 
128     EmitIgnoredExpr(cast<Expr>(S));
129 
130     llvm::BasicBlock *outgoing = Builder.GetInsertBlock();
131     assert(outgoing && "expression emission cleared block!");
132 
133     // The expression emitters assume (reasonably!) that the insertion
134     // point is always set.  To maintain that, the call-emission code
135     // for noreturn functions has to enter a new block with no
136     // predecessors.  We want to kill that block and mark the current
137     // insertion point unreachable in the common case of a call like
138     // "exit();".  Since expression emission doesn't otherwise create
139     // blocks with no predecessors, we can just test for that.
140     // However, we must be careful not to do this to our incoming
141     // block, because *statement* emission does sometimes create
142     // reachable blocks which will have no predecessors until later in
143     // the function.  This occurs with, e.g., labels that are not
144     // reachable by fallthrough.
145     if (incoming != outgoing && outgoing->use_empty()) {
146       outgoing->eraseFromParent();
147       Builder.ClearInsertionPoint();
148     }
149     break;
150   }
151 
152   case Stmt::IndirectGotoStmtClass:
153     EmitIndirectGotoStmt(cast<IndirectGotoStmt>(*S)); break;
154 
155   case Stmt::IfStmtClass:      EmitIfStmt(cast<IfStmt>(*S));              break;
156   case Stmt::WhileStmtClass:   EmitWhileStmt(cast<WhileStmt>(*S), Attrs); break;
157   case Stmt::DoStmtClass:      EmitDoStmt(cast<DoStmt>(*S), Attrs);       break;
158   case Stmt::ForStmtClass:     EmitForStmt(cast<ForStmt>(*S), Attrs);     break;
159 
160   case Stmt::ReturnStmtClass:  EmitReturnStmt(cast<ReturnStmt>(*S));      break;
161 
162   case Stmt::SwitchStmtClass:  EmitSwitchStmt(cast<SwitchStmt>(*S));      break;
163   case Stmt::GCCAsmStmtClass:  // Intentional fall-through.
164   case Stmt::MSAsmStmtClass:   EmitAsmStmt(cast<AsmStmt>(*S));            break;
165   case Stmt::CoroutineBodyStmtClass:
166     EmitCoroutineBody(cast<CoroutineBodyStmt>(*S));
167     break;
168   case Stmt::CoreturnStmtClass:
169     EmitCoreturnStmt(cast<CoreturnStmt>(*S));
170     break;
171   case Stmt::CapturedStmtClass: {
172     const CapturedStmt *CS = cast<CapturedStmt>(S);
173     EmitCapturedStmt(*CS, CS->getCapturedRegionKind());
174     }
175     break;
176   case Stmt::ObjCAtTryStmtClass:
177     EmitObjCAtTryStmt(cast<ObjCAtTryStmt>(*S));
178     break;
179   case Stmt::ObjCAtCatchStmtClass:
180     llvm_unreachable(
181                     "@catch statements should be handled by EmitObjCAtTryStmt");
182   case Stmt::ObjCAtFinallyStmtClass:
183     llvm_unreachable(
184                   "@finally statements should be handled by EmitObjCAtTryStmt");
185   case Stmt::ObjCAtThrowStmtClass:
186     EmitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(*S));
187     break;
188   case Stmt::ObjCAtSynchronizedStmtClass:
189     EmitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(*S));
190     break;
191   case Stmt::ObjCForCollectionStmtClass:
192     EmitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(*S));
193     break;
194   case Stmt::ObjCAutoreleasePoolStmtClass:
195     EmitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(*S));
196     break;
197 
198   case Stmt::CXXTryStmtClass:
199     EmitCXXTryStmt(cast<CXXTryStmt>(*S));
200     break;
201   case Stmt::CXXForRangeStmtClass:
202     EmitCXXForRangeStmt(cast<CXXForRangeStmt>(*S), Attrs);
203     break;
204   case Stmt::SEHTryStmtClass:
205     EmitSEHTryStmt(cast<SEHTryStmt>(*S));
206     break;
207   case Stmt::OMPMetaDirectiveClass:
208     EmitOMPMetaDirective(cast<OMPMetaDirective>(*S));
209     break;
210   case Stmt::OMPCanonicalLoopClass:
211     EmitOMPCanonicalLoop(cast<OMPCanonicalLoop>(S));
212     break;
213   case Stmt::OMPParallelDirectiveClass:
214     EmitOMPParallelDirective(cast<OMPParallelDirective>(*S));
215     break;
216   case Stmt::OMPSimdDirectiveClass:
217     EmitOMPSimdDirective(cast<OMPSimdDirective>(*S));
218     break;
219   case Stmt::OMPTileDirectiveClass:
220     EmitOMPTileDirective(cast<OMPTileDirective>(*S));
221     break;
222   case Stmt::OMPUnrollDirectiveClass:
223     EmitOMPUnrollDirective(cast<OMPUnrollDirective>(*S));
224     break;
225   case Stmt::OMPReverseDirectiveClass:
226     EmitOMPReverseDirective(cast<OMPReverseDirective>(*S));
227     break;
228   case Stmt::OMPInterchangeDirectiveClass:
229     EmitOMPInterchangeDirective(cast<OMPInterchangeDirective>(*S));
230     break;
231   case Stmt::OMPForDirectiveClass:
232     EmitOMPForDirective(cast<OMPForDirective>(*S));
233     break;
234   case Stmt::OMPForSimdDirectiveClass:
235     EmitOMPForSimdDirective(cast<OMPForSimdDirective>(*S));
236     break;
237   case Stmt::OMPSectionsDirectiveClass:
238     EmitOMPSectionsDirective(cast<OMPSectionsDirective>(*S));
239     break;
240   case Stmt::OMPSectionDirectiveClass:
241     EmitOMPSectionDirective(cast<OMPSectionDirective>(*S));
242     break;
243   case Stmt::OMPSingleDirectiveClass:
244     EmitOMPSingleDirective(cast<OMPSingleDirective>(*S));
245     break;
246   case Stmt::OMPMasterDirectiveClass:
247     EmitOMPMasterDirective(cast<OMPMasterDirective>(*S));
248     break;
249   case Stmt::OMPCriticalDirectiveClass:
250     EmitOMPCriticalDirective(cast<OMPCriticalDirective>(*S));
251     break;
252   case Stmt::OMPParallelForDirectiveClass:
253     EmitOMPParallelForDirective(cast<OMPParallelForDirective>(*S));
254     break;
255   case Stmt::OMPParallelForSimdDirectiveClass:
256     EmitOMPParallelForSimdDirective(cast<OMPParallelForSimdDirective>(*S));
257     break;
258   case Stmt::OMPParallelMasterDirectiveClass:
259     EmitOMPParallelMasterDirective(cast<OMPParallelMasterDirective>(*S));
260     break;
261   case Stmt::OMPParallelSectionsDirectiveClass:
262     EmitOMPParallelSectionsDirective(cast<OMPParallelSectionsDirective>(*S));
263     break;
264   case Stmt::OMPTaskDirectiveClass:
265     EmitOMPTaskDirective(cast<OMPTaskDirective>(*S));
266     break;
267   case Stmt::OMPTaskyieldDirectiveClass:
268     EmitOMPTaskyieldDirective(cast<OMPTaskyieldDirective>(*S));
269     break;
270   case Stmt::OMPErrorDirectiveClass:
271     EmitOMPErrorDirective(cast<OMPErrorDirective>(*S));
272     break;
273   case Stmt::OMPBarrierDirectiveClass:
274     EmitOMPBarrierDirective(cast<OMPBarrierDirective>(*S));
275     break;
276   case Stmt::OMPTaskwaitDirectiveClass:
277     EmitOMPTaskwaitDirective(cast<OMPTaskwaitDirective>(*S));
278     break;
279   case Stmt::OMPTaskgroupDirectiveClass:
280     EmitOMPTaskgroupDirective(cast<OMPTaskgroupDirective>(*S));
281     break;
282   case Stmt::OMPFlushDirectiveClass:
283     EmitOMPFlushDirective(cast<OMPFlushDirective>(*S));
284     break;
285   case Stmt::OMPDepobjDirectiveClass:
286     EmitOMPDepobjDirective(cast<OMPDepobjDirective>(*S));
287     break;
288   case Stmt::OMPScanDirectiveClass:
289     EmitOMPScanDirective(cast<OMPScanDirective>(*S));
290     break;
291   case Stmt::OMPOrderedDirectiveClass:
292     EmitOMPOrderedDirective(cast<OMPOrderedDirective>(*S));
293     break;
294   case Stmt::OMPAtomicDirectiveClass:
295     EmitOMPAtomicDirective(cast<OMPAtomicDirective>(*S));
296     break;
297   case Stmt::OMPTargetDirectiveClass:
298     EmitOMPTargetDirective(cast<OMPTargetDirective>(*S));
299     break;
300   case Stmt::OMPTeamsDirectiveClass:
301     EmitOMPTeamsDirective(cast<OMPTeamsDirective>(*S));
302     break;
303   case Stmt::OMPCancellationPointDirectiveClass:
304     EmitOMPCancellationPointDirective(cast<OMPCancellationPointDirective>(*S));
305     break;
306   case Stmt::OMPCancelDirectiveClass:
307     EmitOMPCancelDirective(cast<OMPCancelDirective>(*S));
308     break;
309   case Stmt::OMPTargetDataDirectiveClass:
310     EmitOMPTargetDataDirective(cast<OMPTargetDataDirective>(*S));
311     break;
312   case Stmt::OMPTargetEnterDataDirectiveClass:
313     EmitOMPTargetEnterDataDirective(cast<OMPTargetEnterDataDirective>(*S));
314     break;
315   case Stmt::OMPTargetExitDataDirectiveClass:
316     EmitOMPTargetExitDataDirective(cast<OMPTargetExitDataDirective>(*S));
317     break;
318   case Stmt::OMPTargetParallelDirectiveClass:
319     EmitOMPTargetParallelDirective(cast<OMPTargetParallelDirective>(*S));
320     break;
321   case Stmt::OMPTargetParallelForDirectiveClass:
322     EmitOMPTargetParallelForDirective(cast<OMPTargetParallelForDirective>(*S));
323     break;
324   case Stmt::OMPTaskLoopDirectiveClass:
325     EmitOMPTaskLoopDirective(cast<OMPTaskLoopDirective>(*S));
326     break;
327   case Stmt::OMPTaskLoopSimdDirectiveClass:
328     EmitOMPTaskLoopSimdDirective(cast<OMPTaskLoopSimdDirective>(*S));
329     break;
330   case Stmt::OMPMasterTaskLoopDirectiveClass:
331     EmitOMPMasterTaskLoopDirective(cast<OMPMasterTaskLoopDirective>(*S));
332     break;
333   case Stmt::OMPMaskedTaskLoopDirectiveClass:
334     llvm_unreachable("masked taskloop directive not supported yet.");
335     break;
336   case Stmt::OMPMasterTaskLoopSimdDirectiveClass:
337     EmitOMPMasterTaskLoopSimdDirective(
338         cast<OMPMasterTaskLoopSimdDirective>(*S));
339     break;
340   case Stmt::OMPMaskedTaskLoopSimdDirectiveClass:
341     llvm_unreachable("masked taskloop simd directive not supported yet.");
342     break;
343   case Stmt::OMPParallelMasterTaskLoopDirectiveClass:
344     EmitOMPParallelMasterTaskLoopDirective(
345         cast<OMPParallelMasterTaskLoopDirective>(*S));
346     break;
347   case Stmt::OMPParallelMaskedTaskLoopDirectiveClass:
348     llvm_unreachable("parallel masked taskloop directive not supported yet.");
349     break;
350   case Stmt::OMPParallelMasterTaskLoopSimdDirectiveClass:
351     EmitOMPParallelMasterTaskLoopSimdDirective(
352         cast<OMPParallelMasterTaskLoopSimdDirective>(*S));
353     break;
354   case Stmt::OMPParallelMaskedTaskLoopSimdDirectiveClass:
355     llvm_unreachable(
356         "parallel masked taskloop simd directive not supported yet.");
357     break;
358   case Stmt::OMPDistributeDirectiveClass:
359     EmitOMPDistributeDirective(cast<OMPDistributeDirective>(*S));
360     break;
361   case Stmt::OMPTargetUpdateDirectiveClass:
362     EmitOMPTargetUpdateDirective(cast<OMPTargetUpdateDirective>(*S));
363     break;
364   case Stmt::OMPDistributeParallelForDirectiveClass:
365     EmitOMPDistributeParallelForDirective(
366         cast<OMPDistributeParallelForDirective>(*S));
367     break;
368   case Stmt::OMPDistributeParallelForSimdDirectiveClass:
369     EmitOMPDistributeParallelForSimdDirective(
370         cast<OMPDistributeParallelForSimdDirective>(*S));
371     break;
372   case Stmt::OMPDistributeSimdDirectiveClass:
373     EmitOMPDistributeSimdDirective(cast<OMPDistributeSimdDirective>(*S));
374     break;
375   case Stmt::OMPTargetParallelForSimdDirectiveClass:
376     EmitOMPTargetParallelForSimdDirective(
377         cast<OMPTargetParallelForSimdDirective>(*S));
378     break;
379   case Stmt::OMPTargetSimdDirectiveClass:
380     EmitOMPTargetSimdDirective(cast<OMPTargetSimdDirective>(*S));
381     break;
382   case Stmt::OMPTeamsDistributeDirectiveClass:
383     EmitOMPTeamsDistributeDirective(cast<OMPTeamsDistributeDirective>(*S));
384     break;
385   case Stmt::OMPTeamsDistributeSimdDirectiveClass:
386     EmitOMPTeamsDistributeSimdDirective(
387         cast<OMPTeamsDistributeSimdDirective>(*S));
388     break;
389   case Stmt::OMPTeamsDistributeParallelForSimdDirectiveClass:
390     EmitOMPTeamsDistributeParallelForSimdDirective(
391         cast<OMPTeamsDistributeParallelForSimdDirective>(*S));
392     break;
393   case Stmt::OMPTeamsDistributeParallelForDirectiveClass:
394     EmitOMPTeamsDistributeParallelForDirective(
395         cast<OMPTeamsDistributeParallelForDirective>(*S));
396     break;
397   case Stmt::OMPTargetTeamsDirectiveClass:
398     EmitOMPTargetTeamsDirective(cast<OMPTargetTeamsDirective>(*S));
399     break;
400   case Stmt::OMPTargetTeamsDistributeDirectiveClass:
401     EmitOMPTargetTeamsDistributeDirective(
402         cast<OMPTargetTeamsDistributeDirective>(*S));
403     break;
404   case Stmt::OMPTargetTeamsDistributeParallelForDirectiveClass:
405     EmitOMPTargetTeamsDistributeParallelForDirective(
406         cast<OMPTargetTeamsDistributeParallelForDirective>(*S));
407     break;
408   case Stmt::OMPTargetTeamsDistributeParallelForSimdDirectiveClass:
409     EmitOMPTargetTeamsDistributeParallelForSimdDirective(
410         cast<OMPTargetTeamsDistributeParallelForSimdDirective>(*S));
411     break;
412   case Stmt::OMPTargetTeamsDistributeSimdDirectiveClass:
413     EmitOMPTargetTeamsDistributeSimdDirective(
414         cast<OMPTargetTeamsDistributeSimdDirective>(*S));
415     break;
416   case Stmt::OMPInteropDirectiveClass:
417     EmitOMPInteropDirective(cast<OMPInteropDirective>(*S));
418     break;
419   case Stmt::OMPDispatchDirectiveClass:
420     CGM.ErrorUnsupported(S, "OpenMP dispatch directive");
421     break;
422   case Stmt::OMPScopeDirectiveClass:
423     CGM.ErrorUnsupported(S, "scope with FE outlining");
424     break;
425   case Stmt::OMPMaskedDirectiveClass:
426     EmitOMPMaskedDirective(cast<OMPMaskedDirective>(*S));
427     break;
428   case Stmt::OMPGenericLoopDirectiveClass:
429     EmitOMPGenericLoopDirective(cast<OMPGenericLoopDirective>(*S));
430     break;
431   case Stmt::OMPTeamsGenericLoopDirectiveClass:
432     EmitOMPTeamsGenericLoopDirective(cast<OMPTeamsGenericLoopDirective>(*S));
433     break;
434   case Stmt::OMPTargetTeamsGenericLoopDirectiveClass:
435     EmitOMPTargetTeamsGenericLoopDirective(
436         cast<OMPTargetTeamsGenericLoopDirective>(*S));
437     break;
438   case Stmt::OMPParallelGenericLoopDirectiveClass:
439     EmitOMPParallelGenericLoopDirective(
440         cast<OMPParallelGenericLoopDirective>(*S));
441     break;
442   case Stmt::OMPTargetParallelGenericLoopDirectiveClass:
443     EmitOMPTargetParallelGenericLoopDirective(
444         cast<OMPTargetParallelGenericLoopDirective>(*S));
445     break;
446   case Stmt::OMPParallelMaskedDirectiveClass:
447     EmitOMPParallelMaskedDirective(cast<OMPParallelMaskedDirective>(*S));
448     break;
449   case Stmt::OpenACCComputeConstructClass:
450     EmitOpenACCComputeConstruct(cast<OpenACCComputeConstruct>(*S));
451     break;
452   case Stmt::OpenACCLoopConstructClass:
453     EmitOpenACCLoopConstruct(cast<OpenACCLoopConstruct>(*S));
454     break;
455   }
456 }
457 
EmitSimpleStmt(const Stmt * S,ArrayRef<const Attr * > Attrs)458 bool CodeGenFunction::EmitSimpleStmt(const Stmt *S,
459                                      ArrayRef<const Attr *> Attrs) {
460   switch (S->getStmtClass()) {
461   default:
462     return false;
463   case Stmt::NullStmtClass:
464     break;
465   case Stmt::CompoundStmtClass:
466     EmitCompoundStmt(cast<CompoundStmt>(*S));
467     break;
468   case Stmt::DeclStmtClass:
469     EmitDeclStmt(cast<DeclStmt>(*S));
470     break;
471   case Stmt::LabelStmtClass:
472     EmitLabelStmt(cast<LabelStmt>(*S));
473     break;
474   case Stmt::AttributedStmtClass:
475     EmitAttributedStmt(cast<AttributedStmt>(*S));
476     break;
477   case Stmt::GotoStmtClass:
478     EmitGotoStmt(cast<GotoStmt>(*S));
479     break;
480   case Stmt::BreakStmtClass:
481     EmitBreakStmt(cast<BreakStmt>(*S));
482     break;
483   case Stmt::ContinueStmtClass:
484     EmitContinueStmt(cast<ContinueStmt>(*S));
485     break;
486   case Stmt::DefaultStmtClass:
487     EmitDefaultStmt(cast<DefaultStmt>(*S), Attrs);
488     break;
489   case Stmt::CaseStmtClass:
490     EmitCaseStmt(cast<CaseStmt>(*S), Attrs);
491     break;
492   case Stmt::SEHLeaveStmtClass:
493     EmitSEHLeaveStmt(cast<SEHLeaveStmt>(*S));
494     break;
495   }
496   return true;
497 }
498 
499 /// EmitCompoundStmt - Emit a compound statement {..} node.  If GetLast is true,
500 /// this captures the expression result of the last sub-statement and returns it
501 /// (for use by the statement expression extension).
EmitCompoundStmt(const CompoundStmt & S,bool GetLast,AggValueSlot AggSlot)502 Address CodeGenFunction::EmitCompoundStmt(const CompoundStmt &S, bool GetLast,
503                                           AggValueSlot AggSlot) {
504   PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),S.getLBracLoc(),
505                              "LLVM IR generation of compound statement ('{}')");
506 
507   // Keep track of the current cleanup stack depth, including debug scopes.
508   LexicalScope Scope(*this, S.getSourceRange());
509 
510   return EmitCompoundStmtWithoutScope(S, GetLast, AggSlot);
511 }
512 
513 Address
EmitCompoundStmtWithoutScope(const CompoundStmt & S,bool GetLast,AggValueSlot AggSlot)514 CodeGenFunction::EmitCompoundStmtWithoutScope(const CompoundStmt &S,
515                                               bool GetLast,
516                                               AggValueSlot AggSlot) {
517 
518   const Stmt *ExprResult = S.getStmtExprResult();
519   assert((!GetLast || (GetLast && ExprResult)) &&
520          "If GetLast is true then the CompoundStmt must have a StmtExprResult");
521 
522   Address RetAlloca = Address::invalid();
523 
524   for (auto *CurStmt : S.body()) {
525     if (GetLast && ExprResult == CurStmt) {
526       // We have to special case labels here.  They are statements, but when put
527       // at the end of a statement expression, they yield the value of their
528       // subexpression.  Handle this by walking through all labels we encounter,
529       // emitting them before we evaluate the subexpr.
530       // Similar issues arise for attributed statements.
531       while (!isa<Expr>(ExprResult)) {
532         if (const auto *LS = dyn_cast<LabelStmt>(ExprResult)) {
533           EmitLabel(LS->getDecl());
534           ExprResult = LS->getSubStmt();
535         } else if (const auto *AS = dyn_cast<AttributedStmt>(ExprResult)) {
536           // FIXME: Update this if we ever have attributes that affect the
537           // semantics of an expression.
538           ExprResult = AS->getSubStmt();
539         } else {
540           llvm_unreachable("unknown value statement");
541         }
542       }
543 
544       EnsureInsertPoint();
545 
546       const Expr *E = cast<Expr>(ExprResult);
547       QualType ExprTy = E->getType();
548       if (hasAggregateEvaluationKind(ExprTy)) {
549         EmitAggExpr(E, AggSlot);
550       } else {
551         // We can't return an RValue here because there might be cleanups at
552         // the end of the StmtExpr.  Because of that, we have to emit the result
553         // here into a temporary alloca.
554         RetAlloca = CreateMemTemp(ExprTy);
555         EmitAnyExprToMem(E, RetAlloca, Qualifiers(),
556                          /*IsInit*/ false);
557       }
558     } else {
559       EmitStmt(CurStmt);
560     }
561   }
562 
563   return RetAlloca;
564 }
565 
SimplifyForwardingBlocks(llvm::BasicBlock * BB)566 void CodeGenFunction::SimplifyForwardingBlocks(llvm::BasicBlock *BB) {
567   llvm::BranchInst *BI = dyn_cast<llvm::BranchInst>(BB->getTerminator());
568 
569   // If there is a cleanup stack, then we it isn't worth trying to
570   // simplify this block (we would need to remove it from the scope map
571   // and cleanup entry).
572   if (!EHStack.empty())
573     return;
574 
575   // Can only simplify direct branches.
576   if (!BI || !BI->isUnconditional())
577     return;
578 
579   // Can only simplify empty blocks.
580   if (BI->getIterator() != BB->begin())
581     return;
582 
583   BB->replaceAllUsesWith(BI->getSuccessor(0));
584   BI->eraseFromParent();
585   BB->eraseFromParent();
586 }
587 
EmitBlock(llvm::BasicBlock * BB,bool IsFinished)588 void CodeGenFunction::EmitBlock(llvm::BasicBlock *BB, bool IsFinished) {
589   llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
590 
591   // Fall out of the current block (if necessary).
592   EmitBranch(BB);
593 
594   if (IsFinished && BB->use_empty()) {
595     delete BB;
596     return;
597   }
598 
599   // Place the block after the current block, if possible, or else at
600   // the end of the function.
601   if (CurBB && CurBB->getParent())
602     CurFn->insert(std::next(CurBB->getIterator()), BB);
603   else
604     CurFn->insert(CurFn->end(), BB);
605   Builder.SetInsertPoint(BB);
606 }
607 
EmitBranch(llvm::BasicBlock * Target)608 void CodeGenFunction::EmitBranch(llvm::BasicBlock *Target) {
609   // Emit a branch from the current block to the target one if this
610   // was a real block.  If this was just a fall-through block after a
611   // terminator, don't emit it.
612   llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
613 
614   if (!CurBB || CurBB->getTerminator()) {
615     // If there is no insert point or the previous block is already
616     // terminated, don't touch it.
617   } else {
618     // Otherwise, create a fall-through branch.
619     Builder.CreateBr(Target);
620   }
621 
622   Builder.ClearInsertionPoint();
623 }
624 
EmitBlockAfterUses(llvm::BasicBlock * block)625 void CodeGenFunction::EmitBlockAfterUses(llvm::BasicBlock *block) {
626   bool inserted = false;
627   for (llvm::User *u : block->users()) {
628     if (llvm::Instruction *insn = dyn_cast<llvm::Instruction>(u)) {
629       CurFn->insert(std::next(insn->getParent()->getIterator()), block);
630       inserted = true;
631       break;
632     }
633   }
634 
635   if (!inserted)
636     CurFn->insert(CurFn->end(), block);
637 
638   Builder.SetInsertPoint(block);
639 }
640 
641 CodeGenFunction::JumpDest
getJumpDestForLabel(const LabelDecl * D)642 CodeGenFunction::getJumpDestForLabel(const LabelDecl *D) {
643   JumpDest &Dest = LabelMap[D];
644   if (Dest.isValid()) return Dest;
645 
646   // Create, but don't insert, the new block.
647   Dest = JumpDest(createBasicBlock(D->getName()),
648                   EHScopeStack::stable_iterator::invalid(),
649                   NextCleanupDestIndex++);
650   return Dest;
651 }
652 
EmitLabel(const LabelDecl * D)653 void CodeGenFunction::EmitLabel(const LabelDecl *D) {
654   // Add this label to the current lexical scope if we're within any
655   // normal cleanups.  Jumps "in" to this label --- when permitted by
656   // the language --- may need to be routed around such cleanups.
657   if (EHStack.hasNormalCleanups() && CurLexicalScope)
658     CurLexicalScope->addLabel(D);
659 
660   JumpDest &Dest = LabelMap[D];
661 
662   // If we didn't need a forward reference to this label, just go
663   // ahead and create a destination at the current scope.
664   if (!Dest.isValid()) {
665     Dest = getJumpDestInCurrentScope(D->getName());
666 
667   // Otherwise, we need to give this label a target depth and remove
668   // it from the branch-fixups list.
669   } else {
670     assert(!Dest.getScopeDepth().isValid() && "already emitted label!");
671     Dest.setScopeDepth(EHStack.stable_begin());
672     ResolveBranchFixups(Dest.getBlock());
673   }
674 
675   EmitBlock(Dest.getBlock());
676 
677   // Emit debug info for labels.
678   if (CGDebugInfo *DI = getDebugInfo()) {
679     if (CGM.getCodeGenOpts().hasReducedDebugInfo()) {
680       DI->setLocation(D->getLocation());
681       DI->EmitLabel(D, Builder);
682     }
683   }
684 
685   incrementProfileCounter(D->getStmt());
686 }
687 
688 /// Change the cleanup scope of the labels in this lexical scope to
689 /// match the scope of the enclosing context.
rescopeLabels()690 void CodeGenFunction::LexicalScope::rescopeLabels() {
691   assert(!Labels.empty());
692   EHScopeStack::stable_iterator innermostScope
693     = CGF.EHStack.getInnermostNormalCleanup();
694 
695   // Change the scope depth of all the labels.
696   for (SmallVectorImpl<const LabelDecl*>::const_iterator
697          i = Labels.begin(), e = Labels.end(); i != e; ++i) {
698     assert(CGF.LabelMap.count(*i));
699     JumpDest &dest = CGF.LabelMap.find(*i)->second;
700     assert(dest.getScopeDepth().isValid());
701     assert(innermostScope.encloses(dest.getScopeDepth()));
702     dest.setScopeDepth(innermostScope);
703   }
704 
705   // Reparent the labels if the new scope also has cleanups.
706   if (innermostScope != EHScopeStack::stable_end() && ParentScope) {
707     ParentScope->Labels.append(Labels.begin(), Labels.end());
708   }
709 }
710 
711 
EmitLabelStmt(const LabelStmt & S)712 void CodeGenFunction::EmitLabelStmt(const LabelStmt &S) {
713   EmitLabel(S.getDecl());
714 
715   // IsEHa - emit eha.scope.begin if it's a side entry of a scope
716   if (getLangOpts().EHAsynch && S.isSideEntry())
717     EmitSehCppScopeBegin();
718 
719   EmitStmt(S.getSubStmt());
720 }
721 
EmitAttributedStmt(const AttributedStmt & S)722 void CodeGenFunction::EmitAttributedStmt(const AttributedStmt &S) {
723   bool nomerge = false;
724   bool noinline = false;
725   bool alwaysinline = false;
726   const CallExpr *musttail = nullptr;
727 
728   for (const auto *A : S.getAttrs()) {
729     switch (A->getKind()) {
730     default:
731       break;
732     case attr::NoMerge:
733       nomerge = true;
734       break;
735     case attr::NoInline:
736       noinline = true;
737       break;
738     case attr::AlwaysInline:
739       alwaysinline = true;
740       break;
741     case attr::MustTail: {
742       const Stmt *Sub = S.getSubStmt();
743       const ReturnStmt *R = cast<ReturnStmt>(Sub);
744       musttail = cast<CallExpr>(R->getRetValue()->IgnoreParens());
745     } break;
746     case attr::CXXAssume: {
747       const Expr *Assumption = cast<CXXAssumeAttr>(A)->getAssumption();
748       if (getLangOpts().CXXAssumptions && Builder.GetInsertBlock() &&
749           !Assumption->HasSideEffects(getContext())) {
750         llvm::Value *AssumptionVal = EvaluateExprAsBool(Assumption);
751         Builder.CreateAssumption(AssumptionVal);
752       }
753     } break;
754     }
755   }
756   SaveAndRestore save_nomerge(InNoMergeAttributedStmt, nomerge);
757   SaveAndRestore save_noinline(InNoInlineAttributedStmt, noinline);
758   SaveAndRestore save_alwaysinline(InAlwaysInlineAttributedStmt, alwaysinline);
759   SaveAndRestore save_musttail(MustTailCall, musttail);
760   EmitStmt(S.getSubStmt(), S.getAttrs());
761 }
762 
EmitGotoStmt(const GotoStmt & S)763 void CodeGenFunction::EmitGotoStmt(const GotoStmt &S) {
764   // If this code is reachable then emit a stop point (if generating
765   // debug info). We have to do this ourselves because we are on the
766   // "simple" statement path.
767   if (HaveInsertPoint())
768     EmitStopPoint(&S);
769 
770   EmitBranchThroughCleanup(getJumpDestForLabel(S.getLabel()));
771 }
772 
773 
EmitIndirectGotoStmt(const IndirectGotoStmt & S)774 void CodeGenFunction::EmitIndirectGotoStmt(const IndirectGotoStmt &S) {
775   if (const LabelDecl *Target = S.getConstantTarget()) {
776     EmitBranchThroughCleanup(getJumpDestForLabel(Target));
777     return;
778   }
779 
780   // Ensure that we have an i8* for our PHI node.
781   llvm::Value *V = Builder.CreateBitCast(EmitScalarExpr(S.getTarget()),
782                                          Int8PtrTy, "addr");
783   llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
784 
785   // Get the basic block for the indirect goto.
786   llvm::BasicBlock *IndGotoBB = GetIndirectGotoBlock();
787 
788   // The first instruction in the block has to be the PHI for the switch dest,
789   // add an entry for this branch.
790   cast<llvm::PHINode>(IndGotoBB->begin())->addIncoming(V, CurBB);
791 
792   EmitBranch(IndGotoBB);
793 }
794 
EmitIfStmt(const IfStmt & S)795 void CodeGenFunction::EmitIfStmt(const IfStmt &S) {
796   // The else branch of a consteval if statement is always the only branch that
797   // can be runtime evaluated.
798   if (S.isConsteval()) {
799     const Stmt *Executed = S.isNegatedConsteval() ? S.getThen() : S.getElse();
800     if (Executed) {
801       RunCleanupsScope ExecutedScope(*this);
802       EmitStmt(Executed);
803     }
804     return;
805   }
806 
807   // C99 6.8.4.1: The first substatement is executed if the expression compares
808   // unequal to 0.  The condition must be a scalar type.
809   LexicalScope ConditionScope(*this, S.getCond()->getSourceRange());
810 
811   if (S.getInit())
812     EmitStmt(S.getInit());
813 
814   if (S.getConditionVariable())
815     EmitDecl(*S.getConditionVariable());
816 
817   // If the condition constant folds and can be elided, try to avoid emitting
818   // the condition and the dead arm of the if/else.
819   bool CondConstant;
820   if (ConstantFoldsToSimpleInteger(S.getCond(), CondConstant,
821                                    S.isConstexpr())) {
822     // Figure out which block (then or else) is executed.
823     const Stmt *Executed = S.getThen();
824     const Stmt *Skipped  = S.getElse();
825     if (!CondConstant)  // Condition false?
826       std::swap(Executed, Skipped);
827 
828     // If the skipped block has no labels in it, just emit the executed block.
829     // This avoids emitting dead code and simplifies the CFG substantially.
830     if (S.isConstexpr() || !ContainsLabel(Skipped)) {
831       if (CondConstant)
832         incrementProfileCounter(&S);
833       if (Executed) {
834         RunCleanupsScope ExecutedScope(*this);
835         EmitStmt(Executed);
836       }
837       return;
838     }
839   }
840 
841   // Otherwise, the condition did not fold, or we couldn't elide it.  Just emit
842   // the conditional branch.
843   llvm::BasicBlock *ThenBlock = createBasicBlock("if.then");
844   llvm::BasicBlock *ContBlock = createBasicBlock("if.end");
845   llvm::BasicBlock *ElseBlock = ContBlock;
846   if (S.getElse())
847     ElseBlock = createBasicBlock("if.else");
848 
849   // Prefer the PGO based weights over the likelihood attribute.
850   // When the build isn't optimized the metadata isn't used, so don't generate
851   // it.
852   // Also, differentiate between disabled PGO and a never executed branch with
853   // PGO. Assuming PGO is in use:
854   // - we want to ignore the [[likely]] attribute if the branch is never
855   // executed,
856   // - assuming the profile is poor, preserving the attribute may still be
857   // beneficial.
858   // As an approximation, preserve the attribute only if both the branch and the
859   // parent context were not executed.
860   Stmt::Likelihood LH = Stmt::LH_None;
861   uint64_t ThenCount = getProfileCount(S.getThen());
862   if (!ThenCount && !getCurrentProfileCount() &&
863       CGM.getCodeGenOpts().OptimizationLevel)
864     LH = Stmt::getLikelihood(S.getThen(), S.getElse());
865 
866   // When measuring MC/DC, always fully evaluate the condition up front using
867   // EvaluateExprAsBool() so that the test vector bitmap can be updated prior to
868   // executing the body of the if.then or if.else. This is useful for when
869   // there is a 'return' within the body, but this is particularly beneficial
870   // when one if-stmt is nested within another if-stmt so that all of the MC/DC
871   // updates are kept linear and consistent.
872   if (!CGM.getCodeGenOpts().MCDCCoverage)
873     EmitBranchOnBoolExpr(S.getCond(), ThenBlock, ElseBlock, ThenCount, LH);
874   else {
875     llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
876     Builder.CreateCondBr(BoolCondVal, ThenBlock, ElseBlock);
877   }
878 
879   // Emit the 'then' code.
880   EmitBlock(ThenBlock);
881   if (llvm::EnableSingleByteCoverage)
882     incrementProfileCounter(S.getThen());
883   else
884     incrementProfileCounter(&S);
885   {
886     RunCleanupsScope ThenScope(*this);
887     EmitStmt(S.getThen());
888   }
889   EmitBranch(ContBlock);
890 
891   // Emit the 'else' code if present.
892   if (const Stmt *Else = S.getElse()) {
893     {
894       // There is no need to emit line number for an unconditional branch.
895       auto NL = ApplyDebugLocation::CreateEmpty(*this);
896       EmitBlock(ElseBlock);
897     }
898     // When single byte coverage mode is enabled, add a counter to else block.
899     if (llvm::EnableSingleByteCoverage)
900       incrementProfileCounter(Else);
901     {
902       RunCleanupsScope ElseScope(*this);
903       EmitStmt(Else);
904     }
905     {
906       // There is no need to emit line number for an unconditional branch.
907       auto NL = ApplyDebugLocation::CreateEmpty(*this);
908       EmitBranch(ContBlock);
909     }
910   }
911 
912   // Emit the continuation block for code after the if.
913   EmitBlock(ContBlock, true);
914 
915   // When single byte coverage mode is enabled, add a counter to continuation
916   // block.
917   if (llvm::EnableSingleByteCoverage)
918     incrementProfileCounter(&S);
919 }
920 
checkIfLoopMustProgress(const Expr * ControllingExpression,bool HasEmptyBody)921 bool CodeGenFunction::checkIfLoopMustProgress(const Expr *ControllingExpression,
922                                               bool HasEmptyBody) {
923   if (CGM.getCodeGenOpts().getFiniteLoops() ==
924       CodeGenOptions::FiniteLoopsKind::Never)
925     return false;
926 
927   // Now apply rules for plain C (see  6.8.5.6 in C11).
928   // Loops with constant conditions do not have to make progress in any C
929   // version.
930   // As an extension, we consisider loops whose constant expression
931   // can be constant-folded.
932   Expr::EvalResult Result;
933   bool CondIsConstInt =
934       !ControllingExpression ||
935       (ControllingExpression->EvaluateAsInt(Result, getContext()) &&
936        Result.Val.isInt());
937 
938   bool CondIsTrue = CondIsConstInt && (!ControllingExpression ||
939                                        Result.Val.getInt().getBoolValue());
940 
941   // Loops with non-constant conditions must make progress in C11 and later.
942   if (getLangOpts().C11 && !CondIsConstInt)
943     return true;
944 
945   // [C++26][intro.progress] (DR)
946   // The implementation may assume that any thread will eventually do one of the
947   // following:
948   // [...]
949   // - continue execution of a trivial infinite loop ([stmt.iter.general]).
950   if (CGM.getCodeGenOpts().getFiniteLoops() ==
951           CodeGenOptions::FiniteLoopsKind::Always ||
952       getLangOpts().CPlusPlus11) {
953     if (HasEmptyBody && CondIsTrue) {
954       CurFn->removeFnAttr(llvm::Attribute::MustProgress);
955       return false;
956     }
957     return true;
958   }
959   return false;
960 }
961 
962 // [C++26][stmt.iter.general] (DR)
963 // A trivially empty iteration statement is an iteration statement matching one
964 // of the following forms:
965 //  - while ( expression ) ;
966 //  - while ( expression ) { }
967 //  - do ; while ( expression ) ;
968 //  - do { } while ( expression ) ;
969 //  - for ( init-statement expression(opt); ) ;
970 //  - for ( init-statement expression(opt); ) { }
hasEmptyLoopBody(const LoopStmt & S)971 template <typename LoopStmt> static bool hasEmptyLoopBody(const LoopStmt &S) {
972   if constexpr (std::is_same_v<LoopStmt, ForStmt>) {
973     if (S.getInc())
974       return false;
975   }
976   const Stmt *Body = S.getBody();
977   if (!Body || isa<NullStmt>(Body))
978     return true;
979   if (const CompoundStmt *Compound = dyn_cast<CompoundStmt>(Body))
980     return Compound->body_empty();
981   return false;
982 }
983 
EmitWhileStmt(const WhileStmt & S,ArrayRef<const Attr * > WhileAttrs)984 void CodeGenFunction::EmitWhileStmt(const WhileStmt &S,
985                                     ArrayRef<const Attr *> WhileAttrs) {
986   // Emit the header for the loop, which will also become
987   // the continue target.
988   JumpDest LoopHeader = getJumpDestInCurrentScope("while.cond");
989   EmitBlock(LoopHeader.getBlock());
990 
991   if (CGM.shouldEmitConvergenceTokens())
992     ConvergenceTokenStack.push_back(emitConvergenceLoopToken(
993         LoopHeader.getBlock(), ConvergenceTokenStack.back()));
994 
995   // Create an exit block for when the condition fails, which will
996   // also become the break target.
997   JumpDest LoopExit = getJumpDestInCurrentScope("while.end");
998 
999   // Store the blocks to use for break and continue.
1000   BreakContinueStack.push_back(BreakContinue(LoopExit, LoopHeader));
1001 
1002   // C++ [stmt.while]p2:
1003   //   When the condition of a while statement is a declaration, the
1004   //   scope of the variable that is declared extends from its point
1005   //   of declaration (3.3.2) to the end of the while statement.
1006   //   [...]
1007   //   The object created in a condition is destroyed and created
1008   //   with each iteration of the loop.
1009   RunCleanupsScope ConditionScope(*this);
1010 
1011   if (S.getConditionVariable())
1012     EmitDecl(*S.getConditionVariable());
1013 
1014   // Evaluate the conditional in the while header.  C99 6.8.5.1: The
1015   // evaluation of the controlling expression takes place before each
1016   // execution of the loop body.
1017   llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
1018 
1019   // while(1) is common, avoid extra exit blocks.  Be sure
1020   // to correctly handle break/continue though.
1021   llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal);
1022   bool EmitBoolCondBranch = !C || !C->isOne();
1023   const SourceRange &R = S.getSourceRange();
1024   LoopStack.push(LoopHeader.getBlock(), CGM.getContext(), CGM.getCodeGenOpts(),
1025                  WhileAttrs, SourceLocToDebugLoc(R.getBegin()),
1026                  SourceLocToDebugLoc(R.getEnd()),
1027                  checkIfLoopMustProgress(S.getCond(), hasEmptyLoopBody(S)));
1028 
1029   // When single byte coverage mode is enabled, add a counter to loop condition.
1030   if (llvm::EnableSingleByteCoverage)
1031     incrementProfileCounter(S.getCond());
1032 
1033   // As long as the condition is true, go to the loop body.
1034   llvm::BasicBlock *LoopBody = createBasicBlock("while.body");
1035   if (EmitBoolCondBranch) {
1036     llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
1037     if (ConditionScope.requiresCleanups())
1038       ExitBlock = createBasicBlock("while.exit");
1039     llvm::MDNode *Weights =
1040         createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody()));
1041     if (!Weights && CGM.getCodeGenOpts().OptimizationLevel)
1042       BoolCondVal = emitCondLikelihoodViaExpectIntrinsic(
1043           BoolCondVal, Stmt::getLikelihood(S.getBody()));
1044     Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock, Weights);
1045 
1046     if (ExitBlock != LoopExit.getBlock()) {
1047       EmitBlock(ExitBlock);
1048       EmitBranchThroughCleanup(LoopExit);
1049     }
1050   } else if (const Attr *A = Stmt::getLikelihoodAttr(S.getBody())) {
1051     CGM.getDiags().Report(A->getLocation(),
1052                           diag::warn_attribute_has_no_effect_on_infinite_loop)
1053         << A << A->getRange();
1054     CGM.getDiags().Report(
1055         S.getWhileLoc(),
1056         diag::note_attribute_has_no_effect_on_infinite_loop_here)
1057         << SourceRange(S.getWhileLoc(), S.getRParenLoc());
1058   }
1059 
1060   // Emit the loop body.  We have to emit this in a cleanup scope
1061   // because it might be a singleton DeclStmt.
1062   {
1063     RunCleanupsScope BodyScope(*this);
1064     EmitBlock(LoopBody);
1065     // When single byte coverage mode is enabled, add a counter to the body.
1066     if (llvm::EnableSingleByteCoverage)
1067       incrementProfileCounter(S.getBody());
1068     else
1069       incrementProfileCounter(&S);
1070     EmitStmt(S.getBody());
1071   }
1072 
1073   BreakContinueStack.pop_back();
1074 
1075   // Immediately force cleanup.
1076   ConditionScope.ForceCleanup();
1077 
1078   EmitStopPoint(&S);
1079   // Branch to the loop header again.
1080   EmitBranch(LoopHeader.getBlock());
1081 
1082   LoopStack.pop();
1083 
1084   // Emit the exit block.
1085   EmitBlock(LoopExit.getBlock(), true);
1086 
1087   // The LoopHeader typically is just a branch if we skipped emitting
1088   // a branch, try to erase it.
1089   if (!EmitBoolCondBranch)
1090     SimplifyForwardingBlocks(LoopHeader.getBlock());
1091 
1092   // When single byte coverage mode is enabled, add a counter to continuation
1093   // block.
1094   if (llvm::EnableSingleByteCoverage)
1095     incrementProfileCounter(&S);
1096 
1097   if (CGM.shouldEmitConvergenceTokens())
1098     ConvergenceTokenStack.pop_back();
1099 }
1100 
EmitDoStmt(const DoStmt & S,ArrayRef<const Attr * > DoAttrs)1101 void CodeGenFunction::EmitDoStmt(const DoStmt &S,
1102                                  ArrayRef<const Attr *> DoAttrs) {
1103   JumpDest LoopExit = getJumpDestInCurrentScope("do.end");
1104   JumpDest LoopCond = getJumpDestInCurrentScope("do.cond");
1105 
1106   uint64_t ParentCount = getCurrentProfileCount();
1107 
1108   // Store the blocks to use for break and continue.
1109   BreakContinueStack.push_back(BreakContinue(LoopExit, LoopCond));
1110 
1111   // Emit the body of the loop.
1112   llvm::BasicBlock *LoopBody = createBasicBlock("do.body");
1113 
1114   if (llvm::EnableSingleByteCoverage)
1115     EmitBlockWithFallThrough(LoopBody, S.getBody());
1116   else
1117     EmitBlockWithFallThrough(LoopBody, &S);
1118 
1119   if (CGM.shouldEmitConvergenceTokens())
1120     ConvergenceTokenStack.push_back(
1121         emitConvergenceLoopToken(LoopBody, ConvergenceTokenStack.back()));
1122 
1123   {
1124     RunCleanupsScope BodyScope(*this);
1125     EmitStmt(S.getBody());
1126   }
1127 
1128   EmitBlock(LoopCond.getBlock());
1129   // When single byte coverage mode is enabled, add a counter to loop condition.
1130   if (llvm::EnableSingleByteCoverage)
1131     incrementProfileCounter(S.getCond());
1132 
1133   // C99 6.8.5.2: "The evaluation of the controlling expression takes place
1134   // after each execution of the loop body."
1135 
1136   // Evaluate the conditional in the while header.
1137   // C99 6.8.5p2/p4: The first substatement is executed if the expression
1138   // compares unequal to 0.  The condition must be a scalar type.
1139   llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
1140 
1141   BreakContinueStack.pop_back();
1142 
1143   // "do {} while (0)" is common in macros, avoid extra blocks.  Be sure
1144   // to correctly handle break/continue though.
1145   llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal);
1146   bool EmitBoolCondBranch = !C || !C->isZero();
1147 
1148   const SourceRange &R = S.getSourceRange();
1149   LoopStack.push(LoopBody, CGM.getContext(), CGM.getCodeGenOpts(), DoAttrs,
1150                  SourceLocToDebugLoc(R.getBegin()),
1151                  SourceLocToDebugLoc(R.getEnd()),
1152                  checkIfLoopMustProgress(S.getCond(), hasEmptyLoopBody(S)));
1153 
1154   // As long as the condition is true, iterate the loop.
1155   if (EmitBoolCondBranch) {
1156     uint64_t BackedgeCount = getProfileCount(S.getBody()) - ParentCount;
1157     Builder.CreateCondBr(
1158         BoolCondVal, LoopBody, LoopExit.getBlock(),
1159         createProfileWeightsForLoop(S.getCond(), BackedgeCount));
1160   }
1161 
1162   LoopStack.pop();
1163 
1164   // Emit the exit block.
1165   EmitBlock(LoopExit.getBlock());
1166 
1167   // The DoCond block typically is just a branch if we skipped
1168   // emitting a branch, try to erase it.
1169   if (!EmitBoolCondBranch)
1170     SimplifyForwardingBlocks(LoopCond.getBlock());
1171 
1172   // When single byte coverage mode is enabled, add a counter to continuation
1173   // block.
1174   if (llvm::EnableSingleByteCoverage)
1175     incrementProfileCounter(&S);
1176 
1177   if (CGM.shouldEmitConvergenceTokens())
1178     ConvergenceTokenStack.pop_back();
1179 }
1180 
EmitForStmt(const ForStmt & S,ArrayRef<const Attr * > ForAttrs)1181 void CodeGenFunction::EmitForStmt(const ForStmt &S,
1182                                   ArrayRef<const Attr *> ForAttrs) {
1183   JumpDest LoopExit = getJumpDestInCurrentScope("for.end");
1184 
1185   LexicalScope ForScope(*this, S.getSourceRange());
1186 
1187   // Evaluate the first part before the loop.
1188   if (S.getInit())
1189     EmitStmt(S.getInit());
1190 
1191   // Start the loop with a block that tests the condition.
1192   // If there's an increment, the continue scope will be overwritten
1193   // later.
1194   JumpDest CondDest = getJumpDestInCurrentScope("for.cond");
1195   llvm::BasicBlock *CondBlock = CondDest.getBlock();
1196   EmitBlock(CondBlock);
1197 
1198   if (CGM.shouldEmitConvergenceTokens())
1199     ConvergenceTokenStack.push_back(
1200         emitConvergenceLoopToken(CondBlock, ConvergenceTokenStack.back()));
1201 
1202   const SourceRange &R = S.getSourceRange();
1203   LoopStack.push(CondBlock, CGM.getContext(), CGM.getCodeGenOpts(), ForAttrs,
1204                  SourceLocToDebugLoc(R.getBegin()),
1205                  SourceLocToDebugLoc(R.getEnd()),
1206                  checkIfLoopMustProgress(S.getCond(), hasEmptyLoopBody(S)));
1207 
1208   // Create a cleanup scope for the condition variable cleanups.
1209   LexicalScope ConditionScope(*this, S.getSourceRange());
1210 
1211   // If the for loop doesn't have an increment we can just use the condition as
1212   // the continue block. Otherwise, if there is no condition variable, we can
1213   // form the continue block now. If there is a condition variable, we can't
1214   // form the continue block until after we've emitted the condition, because
1215   // the condition is in scope in the increment, but Sema's jump diagnostics
1216   // ensure that there are no continues from the condition variable that jump
1217   // to the loop increment.
1218   JumpDest Continue;
1219   if (!S.getInc())
1220     Continue = CondDest;
1221   else if (!S.getConditionVariable())
1222     Continue = getJumpDestInCurrentScope("for.inc");
1223   BreakContinueStack.push_back(BreakContinue(LoopExit, Continue));
1224 
1225   if (S.getCond()) {
1226     // If the for statement has a condition scope, emit the local variable
1227     // declaration.
1228     if (S.getConditionVariable()) {
1229       EmitDecl(*S.getConditionVariable());
1230 
1231       // We have entered the condition variable's scope, so we're now able to
1232       // jump to the continue block.
1233       Continue = S.getInc() ? getJumpDestInCurrentScope("for.inc") : CondDest;
1234       BreakContinueStack.back().ContinueBlock = Continue;
1235     }
1236 
1237     // When single byte coverage mode is enabled, add a counter to loop
1238     // condition.
1239     if (llvm::EnableSingleByteCoverage)
1240       incrementProfileCounter(S.getCond());
1241 
1242     llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
1243     // If there are any cleanups between here and the loop-exit scope,
1244     // create a block to stage a loop exit along.
1245     if (ForScope.requiresCleanups())
1246       ExitBlock = createBasicBlock("for.cond.cleanup");
1247 
1248     // As long as the condition is true, iterate the loop.
1249     llvm::BasicBlock *ForBody = createBasicBlock("for.body");
1250 
1251     // C99 6.8.5p2/p4: The first substatement is executed if the expression
1252     // compares unequal to 0.  The condition must be a scalar type.
1253     llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
1254     llvm::MDNode *Weights =
1255         createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody()));
1256     if (!Weights && CGM.getCodeGenOpts().OptimizationLevel)
1257       BoolCondVal = emitCondLikelihoodViaExpectIntrinsic(
1258           BoolCondVal, Stmt::getLikelihood(S.getBody()));
1259 
1260     Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock, Weights);
1261 
1262     if (ExitBlock != LoopExit.getBlock()) {
1263       EmitBlock(ExitBlock);
1264       EmitBranchThroughCleanup(LoopExit);
1265     }
1266 
1267     EmitBlock(ForBody);
1268   } else {
1269     // Treat it as a non-zero constant.  Don't even create a new block for the
1270     // body, just fall into it.
1271   }
1272 
1273   // When single byte coverage mode is enabled, add a counter to the body.
1274   if (llvm::EnableSingleByteCoverage)
1275     incrementProfileCounter(S.getBody());
1276   else
1277     incrementProfileCounter(&S);
1278   {
1279     // Create a separate cleanup scope for the body, in case it is not
1280     // a compound statement.
1281     RunCleanupsScope BodyScope(*this);
1282     EmitStmt(S.getBody());
1283   }
1284 
1285   // If there is an increment, emit it next.
1286   if (S.getInc()) {
1287     EmitBlock(Continue.getBlock());
1288     EmitStmt(S.getInc());
1289     if (llvm::EnableSingleByteCoverage)
1290       incrementProfileCounter(S.getInc());
1291   }
1292 
1293   BreakContinueStack.pop_back();
1294 
1295   ConditionScope.ForceCleanup();
1296 
1297   EmitStopPoint(&S);
1298   EmitBranch(CondBlock);
1299 
1300   ForScope.ForceCleanup();
1301 
1302   LoopStack.pop();
1303 
1304   // Emit the fall-through block.
1305   EmitBlock(LoopExit.getBlock(), true);
1306 
1307   // When single byte coverage mode is enabled, add a counter to continuation
1308   // block.
1309   if (llvm::EnableSingleByteCoverage)
1310     incrementProfileCounter(&S);
1311 
1312   if (CGM.shouldEmitConvergenceTokens())
1313     ConvergenceTokenStack.pop_back();
1314 }
1315 
1316 void
EmitCXXForRangeStmt(const CXXForRangeStmt & S,ArrayRef<const Attr * > ForAttrs)1317 CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S,
1318                                      ArrayRef<const Attr *> ForAttrs) {
1319   JumpDest LoopExit = getJumpDestInCurrentScope("for.end");
1320 
1321   LexicalScope ForScope(*this, S.getSourceRange());
1322 
1323   // Evaluate the first pieces before the loop.
1324   if (S.getInit())
1325     EmitStmt(S.getInit());
1326   EmitStmt(S.getRangeStmt());
1327   EmitStmt(S.getBeginStmt());
1328   EmitStmt(S.getEndStmt());
1329 
1330   // Start the loop with a block that tests the condition.
1331   // If there's an increment, the continue scope will be overwritten
1332   // later.
1333   llvm::BasicBlock *CondBlock = createBasicBlock("for.cond");
1334   EmitBlock(CondBlock);
1335 
1336   if (CGM.shouldEmitConvergenceTokens())
1337     ConvergenceTokenStack.push_back(
1338         emitConvergenceLoopToken(CondBlock, ConvergenceTokenStack.back()));
1339 
1340   const SourceRange &R = S.getSourceRange();
1341   LoopStack.push(CondBlock, CGM.getContext(), CGM.getCodeGenOpts(), ForAttrs,
1342                  SourceLocToDebugLoc(R.getBegin()),
1343                  SourceLocToDebugLoc(R.getEnd()));
1344 
1345   // If there are any cleanups between here and the loop-exit scope,
1346   // create a block to stage a loop exit along.
1347   llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
1348   if (ForScope.requiresCleanups())
1349     ExitBlock = createBasicBlock("for.cond.cleanup");
1350 
1351   // The loop body, consisting of the specified body and the loop variable.
1352   llvm::BasicBlock *ForBody = createBasicBlock("for.body");
1353 
1354   // The body is executed if the expression, contextually converted
1355   // to bool, is true.
1356   llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
1357   llvm::MDNode *Weights =
1358       createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody()));
1359   if (!Weights && CGM.getCodeGenOpts().OptimizationLevel)
1360     BoolCondVal = emitCondLikelihoodViaExpectIntrinsic(
1361         BoolCondVal, Stmt::getLikelihood(S.getBody()));
1362   Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock, Weights);
1363 
1364   if (ExitBlock != LoopExit.getBlock()) {
1365     EmitBlock(ExitBlock);
1366     EmitBranchThroughCleanup(LoopExit);
1367   }
1368 
1369   EmitBlock(ForBody);
1370   if (llvm::EnableSingleByteCoverage)
1371     incrementProfileCounter(S.getBody());
1372   else
1373     incrementProfileCounter(&S);
1374 
1375   // Create a block for the increment. In case of a 'continue', we jump there.
1376   JumpDest Continue = getJumpDestInCurrentScope("for.inc");
1377 
1378   // Store the blocks to use for break and continue.
1379   BreakContinueStack.push_back(BreakContinue(LoopExit, Continue));
1380 
1381   {
1382     // Create a separate cleanup scope for the loop variable and body.
1383     LexicalScope BodyScope(*this, S.getSourceRange());
1384     EmitStmt(S.getLoopVarStmt());
1385     EmitStmt(S.getBody());
1386   }
1387 
1388   EmitStopPoint(&S);
1389   // If there is an increment, emit it next.
1390   EmitBlock(Continue.getBlock());
1391   EmitStmt(S.getInc());
1392 
1393   BreakContinueStack.pop_back();
1394 
1395   EmitBranch(CondBlock);
1396 
1397   ForScope.ForceCleanup();
1398 
1399   LoopStack.pop();
1400 
1401   // Emit the fall-through block.
1402   EmitBlock(LoopExit.getBlock(), true);
1403 
1404   // When single byte coverage mode is enabled, add a counter to continuation
1405   // block.
1406   if (llvm::EnableSingleByteCoverage)
1407     incrementProfileCounter(&S);
1408 
1409   if (CGM.shouldEmitConvergenceTokens())
1410     ConvergenceTokenStack.pop_back();
1411 }
1412 
EmitReturnOfRValue(RValue RV,QualType Ty)1413 void CodeGenFunction::EmitReturnOfRValue(RValue RV, QualType Ty) {
1414   if (RV.isScalar()) {
1415     Builder.CreateStore(RV.getScalarVal(), ReturnValue);
1416   } else if (RV.isAggregate()) {
1417     LValue Dest = MakeAddrLValue(ReturnValue, Ty);
1418     LValue Src = MakeAddrLValue(RV.getAggregateAddress(), Ty);
1419     EmitAggregateCopy(Dest, Src, Ty, getOverlapForReturnValue());
1420   } else {
1421     EmitStoreOfComplex(RV.getComplexVal(), MakeAddrLValue(ReturnValue, Ty),
1422                        /*init*/ true);
1423   }
1424   EmitBranchThroughCleanup(ReturnBlock);
1425 }
1426 
1427 namespace {
1428 // RAII struct used to save and restore a return statment's result expression.
1429 struct SaveRetExprRAII {
SaveRetExprRAII__anon725605700111::SaveRetExprRAII1430   SaveRetExprRAII(const Expr *RetExpr, CodeGenFunction &CGF)
1431       : OldRetExpr(CGF.RetExpr), CGF(CGF) {
1432     CGF.RetExpr = RetExpr;
1433   }
~SaveRetExprRAII__anon725605700111::SaveRetExprRAII1434   ~SaveRetExprRAII() { CGF.RetExpr = OldRetExpr; }
1435   const Expr *OldRetExpr;
1436   CodeGenFunction &CGF;
1437 };
1438 } // namespace
1439 
1440 /// Determine if the given call uses the swiftasync calling convention.
isSwiftAsyncCallee(const CallExpr * CE)1441 static bool isSwiftAsyncCallee(const CallExpr *CE) {
1442   auto calleeQualType = CE->getCallee()->getType();
1443   const FunctionType *calleeType = nullptr;
1444   if (calleeQualType->isFunctionPointerType() ||
1445       calleeQualType->isFunctionReferenceType() ||
1446       calleeQualType->isBlockPointerType() ||
1447       calleeQualType->isMemberFunctionPointerType()) {
1448     calleeType = calleeQualType->getPointeeType()->castAs<FunctionType>();
1449   } else if (auto *ty = dyn_cast<FunctionType>(calleeQualType)) {
1450     calleeType = ty;
1451   } else if (auto CMCE = dyn_cast<CXXMemberCallExpr>(CE)) {
1452     if (auto methodDecl = CMCE->getMethodDecl()) {
1453       // getMethodDecl() doesn't handle member pointers at the moment.
1454       calleeType = methodDecl->getType()->castAs<FunctionType>();
1455     } else {
1456       return false;
1457     }
1458   } else {
1459     return false;
1460   }
1461   return calleeType->getCallConv() == CallingConv::CC_SwiftAsync;
1462 }
1463 
1464 /// EmitReturnStmt - Note that due to GCC extensions, this can have an operand
1465 /// if the function returns void, or may be missing one if the function returns
1466 /// non-void.  Fun stuff :).
EmitReturnStmt(const ReturnStmt & S)1467 void CodeGenFunction::EmitReturnStmt(const ReturnStmt &S) {
1468   if (requiresReturnValueCheck()) {
1469     llvm::Constant *SLoc = EmitCheckSourceLocation(S.getBeginLoc());
1470     auto *SLocPtr =
1471         new llvm::GlobalVariable(CGM.getModule(), SLoc->getType(), false,
1472                                  llvm::GlobalVariable::PrivateLinkage, SLoc);
1473     SLocPtr->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
1474     CGM.getSanitizerMetadata()->disableSanitizerForGlobal(SLocPtr);
1475     assert(ReturnLocation.isValid() && "No valid return location");
1476     Builder.CreateStore(SLocPtr, ReturnLocation);
1477   }
1478 
1479   // Returning from an outlined SEH helper is UB, and we already warn on it.
1480   if (IsOutlinedSEHHelper) {
1481     Builder.CreateUnreachable();
1482     Builder.ClearInsertionPoint();
1483   }
1484 
1485   // Emit the result value, even if unused, to evaluate the side effects.
1486   const Expr *RV = S.getRetValue();
1487 
1488   // Record the result expression of the return statement. The recorded
1489   // expression is used to determine whether a block capture's lifetime should
1490   // end at the end of the full expression as opposed to the end of the scope
1491   // enclosing the block expression.
1492   //
1493   // This permits a small, easily-implemented exception to our over-conservative
1494   // rules about not jumping to statements following block literals with
1495   // non-trivial cleanups.
1496   SaveRetExprRAII SaveRetExpr(RV, *this);
1497 
1498   RunCleanupsScope cleanupScope(*this);
1499   if (const auto *EWC = dyn_cast_or_null<ExprWithCleanups>(RV))
1500     RV = EWC->getSubExpr();
1501 
1502   // If we're in a swiftasynccall function, and the return expression is a
1503   // call to a swiftasynccall function, mark the call as the musttail call.
1504   std::optional<llvm::SaveAndRestore<const CallExpr *>> SaveMustTail;
1505   if (RV && CurFnInfo &&
1506       CurFnInfo->getASTCallingConvention() == CallingConv::CC_SwiftAsync) {
1507     if (auto CE = dyn_cast<CallExpr>(RV)) {
1508       if (isSwiftAsyncCallee(CE)) {
1509         SaveMustTail.emplace(MustTailCall, CE);
1510       }
1511     }
1512   }
1513 
1514   // FIXME: Clean this up by using an LValue for ReturnTemp,
1515   // EmitStoreThroughLValue, and EmitAnyExpr.
1516   // Check if the NRVO candidate was not globalized in OpenMP mode.
1517   if (getLangOpts().ElideConstructors && S.getNRVOCandidate() &&
1518       S.getNRVOCandidate()->isNRVOVariable() &&
1519       (!getLangOpts().OpenMP ||
1520        !CGM.getOpenMPRuntime()
1521             .getAddressOfLocalVariable(*this, S.getNRVOCandidate())
1522             .isValid())) {
1523     // Apply the named return value optimization for this return statement,
1524     // which means doing nothing: the appropriate result has already been
1525     // constructed into the NRVO variable.
1526 
1527     // If there is an NRVO flag for this variable, set it to 1 into indicate
1528     // that the cleanup code should not destroy the variable.
1529     if (llvm::Value *NRVOFlag = NRVOFlags[S.getNRVOCandidate()])
1530       Builder.CreateFlagStore(Builder.getTrue(), NRVOFlag);
1531   } else if (!ReturnValue.isValid() || (RV && RV->getType()->isVoidType())) {
1532     // Make sure not to return anything, but evaluate the expression
1533     // for side effects.
1534     if (RV) {
1535       EmitAnyExpr(RV);
1536     }
1537   } else if (!RV) {
1538     // Do nothing (return value is left uninitialized)
1539   } else if (FnRetTy->isReferenceType()) {
1540     // If this function returns a reference, take the address of the expression
1541     // rather than the value.
1542     RValue Result = EmitReferenceBindingToExpr(RV);
1543     Builder.CreateStore(Result.getScalarVal(), ReturnValue);
1544   } else {
1545     switch (getEvaluationKind(RV->getType())) {
1546     case TEK_Scalar: {
1547       llvm::Value *Ret = EmitScalarExpr(RV);
1548       if (CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::Indirect)
1549         EmitStoreOfScalar(Ret, MakeAddrLValue(ReturnValue, RV->getType()),
1550                           /*isInit*/ true);
1551       else
1552         Builder.CreateStore(Ret, ReturnValue);
1553       break;
1554     }
1555     case TEK_Complex:
1556       EmitComplexExprIntoLValue(RV, MakeAddrLValue(ReturnValue, RV->getType()),
1557                                 /*isInit*/ true);
1558       break;
1559     case TEK_Aggregate:
1560       EmitAggExpr(RV, AggValueSlot::forAddr(
1561                           ReturnValue, Qualifiers(),
1562                           AggValueSlot::IsDestructed,
1563                           AggValueSlot::DoesNotNeedGCBarriers,
1564                           AggValueSlot::IsNotAliased,
1565                           getOverlapForReturnValue()));
1566       break;
1567     }
1568   }
1569 
1570   ++NumReturnExprs;
1571   if (!RV || RV->isEvaluatable(getContext()))
1572     ++NumSimpleReturnExprs;
1573 
1574   cleanupScope.ForceCleanup();
1575   EmitBranchThroughCleanup(ReturnBlock);
1576 }
1577 
EmitDeclStmt(const DeclStmt & S)1578 void CodeGenFunction::EmitDeclStmt(const DeclStmt &S) {
1579   // As long as debug info is modeled with instructions, we have to ensure we
1580   // have a place to insert here and write the stop point here.
1581   if (HaveInsertPoint())
1582     EmitStopPoint(&S);
1583 
1584   for (const auto *I : S.decls())
1585     EmitDecl(*I);
1586 }
1587 
EmitBreakStmt(const BreakStmt & S)1588 void CodeGenFunction::EmitBreakStmt(const BreakStmt &S) {
1589   assert(!BreakContinueStack.empty() && "break stmt not in a loop or switch!");
1590 
1591   // If this code is reachable then emit a stop point (if generating
1592   // debug info). We have to do this ourselves because we are on the
1593   // "simple" statement path.
1594   if (HaveInsertPoint())
1595     EmitStopPoint(&S);
1596 
1597   EmitBranchThroughCleanup(BreakContinueStack.back().BreakBlock);
1598 }
1599 
EmitContinueStmt(const ContinueStmt & S)1600 void CodeGenFunction::EmitContinueStmt(const ContinueStmt &S) {
1601   assert(!BreakContinueStack.empty() && "continue stmt not in a loop!");
1602 
1603   // If this code is reachable then emit a stop point (if generating
1604   // debug info). We have to do this ourselves because we are on the
1605   // "simple" statement path.
1606   if (HaveInsertPoint())
1607     EmitStopPoint(&S);
1608 
1609   EmitBranchThroughCleanup(BreakContinueStack.back().ContinueBlock);
1610 }
1611 
1612 /// EmitCaseStmtRange - If case statement range is not too big then
1613 /// add multiple cases to switch instruction, one for each value within
1614 /// the range. If range is too big then emit "if" condition check.
EmitCaseStmtRange(const CaseStmt & S,ArrayRef<const Attr * > Attrs)1615 void CodeGenFunction::EmitCaseStmtRange(const CaseStmt &S,
1616                                         ArrayRef<const Attr *> Attrs) {
1617   assert(S.getRHS() && "Expected RHS value in CaseStmt");
1618 
1619   llvm::APSInt LHS = S.getLHS()->EvaluateKnownConstInt(getContext());
1620   llvm::APSInt RHS = S.getRHS()->EvaluateKnownConstInt(getContext());
1621 
1622   // Emit the code for this case. We do this first to make sure it is
1623   // properly chained from our predecessor before generating the
1624   // switch machinery to enter this block.
1625   llvm::BasicBlock *CaseDest = createBasicBlock("sw.bb");
1626   EmitBlockWithFallThrough(CaseDest, &S);
1627   EmitStmt(S.getSubStmt());
1628 
1629   // If range is empty, do nothing.
1630   if (LHS.isSigned() ? RHS.slt(LHS) : RHS.ult(LHS))
1631     return;
1632 
1633   Stmt::Likelihood LH = Stmt::getLikelihood(Attrs);
1634   llvm::APInt Range = RHS - LHS;
1635   // FIXME: parameters such as this should not be hardcoded.
1636   if (Range.ult(llvm::APInt(Range.getBitWidth(), 64))) {
1637     // Range is small enough to add multiple switch instruction cases.
1638     uint64_t Total = getProfileCount(&S);
1639     unsigned NCases = Range.getZExtValue() + 1;
1640     // We only have one region counter for the entire set of cases here, so we
1641     // need to divide the weights evenly between the generated cases, ensuring
1642     // that the total weight is preserved. E.g., a weight of 5 over three cases
1643     // will be distributed as weights of 2, 2, and 1.
1644     uint64_t Weight = Total / NCases, Rem = Total % NCases;
1645     for (unsigned I = 0; I != NCases; ++I) {
1646       if (SwitchWeights)
1647         SwitchWeights->push_back(Weight + (Rem ? 1 : 0));
1648       else if (SwitchLikelihood)
1649         SwitchLikelihood->push_back(LH);
1650 
1651       if (Rem)
1652         Rem--;
1653       SwitchInsn->addCase(Builder.getInt(LHS), CaseDest);
1654       ++LHS;
1655     }
1656     return;
1657   }
1658 
1659   // The range is too big. Emit "if" condition into a new block,
1660   // making sure to save and restore the current insertion point.
1661   llvm::BasicBlock *RestoreBB = Builder.GetInsertBlock();
1662 
1663   // Push this test onto the chain of range checks (which terminates
1664   // in the default basic block). The switch's default will be changed
1665   // to the top of this chain after switch emission is complete.
1666   llvm::BasicBlock *FalseDest = CaseRangeBlock;
1667   CaseRangeBlock = createBasicBlock("sw.caserange");
1668 
1669   CurFn->insert(CurFn->end(), CaseRangeBlock);
1670   Builder.SetInsertPoint(CaseRangeBlock);
1671 
1672   // Emit range check.
1673   llvm::Value *Diff =
1674     Builder.CreateSub(SwitchInsn->getCondition(), Builder.getInt(LHS));
1675   llvm::Value *Cond =
1676     Builder.CreateICmpULE(Diff, Builder.getInt(Range), "inbounds");
1677 
1678   llvm::MDNode *Weights = nullptr;
1679   if (SwitchWeights) {
1680     uint64_t ThisCount = getProfileCount(&S);
1681     uint64_t DefaultCount = (*SwitchWeights)[0];
1682     Weights = createProfileWeights(ThisCount, DefaultCount);
1683 
1684     // Since we're chaining the switch default through each large case range, we
1685     // need to update the weight for the default, ie, the first case, to include
1686     // this case.
1687     (*SwitchWeights)[0] += ThisCount;
1688   } else if (SwitchLikelihood)
1689     Cond = emitCondLikelihoodViaExpectIntrinsic(Cond, LH);
1690 
1691   Builder.CreateCondBr(Cond, CaseDest, FalseDest, Weights);
1692 
1693   // Restore the appropriate insertion point.
1694   if (RestoreBB)
1695     Builder.SetInsertPoint(RestoreBB);
1696   else
1697     Builder.ClearInsertionPoint();
1698 }
1699 
EmitCaseStmt(const CaseStmt & S,ArrayRef<const Attr * > Attrs)1700 void CodeGenFunction::EmitCaseStmt(const CaseStmt &S,
1701                                    ArrayRef<const Attr *> Attrs) {
1702   // If there is no enclosing switch instance that we're aware of, then this
1703   // case statement and its block can be elided.  This situation only happens
1704   // when we've constant-folded the switch, are emitting the constant case,
1705   // and part of the constant case includes another case statement.  For
1706   // instance: switch (4) { case 4: do { case 5: } while (1); }
1707   if (!SwitchInsn) {
1708     EmitStmt(S.getSubStmt());
1709     return;
1710   }
1711 
1712   // Handle case ranges.
1713   if (S.getRHS()) {
1714     EmitCaseStmtRange(S, Attrs);
1715     return;
1716   }
1717 
1718   llvm::ConstantInt *CaseVal =
1719     Builder.getInt(S.getLHS()->EvaluateKnownConstInt(getContext()));
1720 
1721   // Emit debuginfo for the case value if it is an enum value.
1722   const ConstantExpr *CE;
1723   if (auto ICE = dyn_cast<ImplicitCastExpr>(S.getLHS()))
1724     CE = dyn_cast<ConstantExpr>(ICE->getSubExpr());
1725   else
1726     CE = dyn_cast<ConstantExpr>(S.getLHS());
1727   if (CE) {
1728     if (auto DE = dyn_cast<DeclRefExpr>(CE->getSubExpr()))
1729       if (CGDebugInfo *Dbg = getDebugInfo())
1730         if (CGM.getCodeGenOpts().hasReducedDebugInfo())
1731           Dbg->EmitGlobalVariable(DE->getDecl(),
1732               APValue(llvm::APSInt(CaseVal->getValue())));
1733   }
1734 
1735   if (SwitchLikelihood)
1736     SwitchLikelihood->push_back(Stmt::getLikelihood(Attrs));
1737 
1738   // If the body of the case is just a 'break', try to not emit an empty block.
1739   // If we're profiling or we're not optimizing, leave the block in for better
1740   // debug and coverage analysis.
1741   if (!CGM.getCodeGenOpts().hasProfileClangInstr() &&
1742       CGM.getCodeGenOpts().OptimizationLevel > 0 &&
1743       isa<BreakStmt>(S.getSubStmt())) {
1744     JumpDest Block = BreakContinueStack.back().BreakBlock;
1745 
1746     // Only do this optimization if there are no cleanups that need emitting.
1747     if (isObviouslyBranchWithoutCleanups(Block)) {
1748       if (SwitchWeights)
1749         SwitchWeights->push_back(getProfileCount(&S));
1750       SwitchInsn->addCase(CaseVal, Block.getBlock());
1751 
1752       // If there was a fallthrough into this case, make sure to redirect it to
1753       // the end of the switch as well.
1754       if (Builder.GetInsertBlock()) {
1755         Builder.CreateBr(Block.getBlock());
1756         Builder.ClearInsertionPoint();
1757       }
1758       return;
1759     }
1760   }
1761 
1762   llvm::BasicBlock *CaseDest = createBasicBlock("sw.bb");
1763   EmitBlockWithFallThrough(CaseDest, &S);
1764   if (SwitchWeights)
1765     SwitchWeights->push_back(getProfileCount(&S));
1766   SwitchInsn->addCase(CaseVal, CaseDest);
1767 
1768   // Recursively emitting the statement is acceptable, but is not wonderful for
1769   // code where we have many case statements nested together, i.e.:
1770   //  case 1:
1771   //    case 2:
1772   //      case 3: etc.
1773   // Handling this recursively will create a new block for each case statement
1774   // that falls through to the next case which is IR intensive.  It also causes
1775   // deep recursion which can run into stack depth limitations.  Handle
1776   // sequential non-range case statements specially.
1777   //
1778   // TODO When the next case has a likelihood attribute the code returns to the
1779   // recursive algorithm. Maybe improve this case if it becomes common practice
1780   // to use a lot of attributes.
1781   const CaseStmt *CurCase = &S;
1782   const CaseStmt *NextCase = dyn_cast<CaseStmt>(S.getSubStmt());
1783 
1784   // Otherwise, iteratively add consecutive cases to this switch stmt.
1785   while (NextCase && NextCase->getRHS() == nullptr) {
1786     CurCase = NextCase;
1787     llvm::ConstantInt *CaseVal =
1788       Builder.getInt(CurCase->getLHS()->EvaluateKnownConstInt(getContext()));
1789 
1790     if (SwitchWeights)
1791       SwitchWeights->push_back(getProfileCount(NextCase));
1792     if (CGM.getCodeGenOpts().hasProfileClangInstr()) {
1793       CaseDest = createBasicBlock("sw.bb");
1794       EmitBlockWithFallThrough(CaseDest, CurCase);
1795     }
1796     // Since this loop is only executed when the CaseStmt has no attributes
1797     // use a hard-coded value.
1798     if (SwitchLikelihood)
1799       SwitchLikelihood->push_back(Stmt::LH_None);
1800 
1801     SwitchInsn->addCase(CaseVal, CaseDest);
1802     NextCase = dyn_cast<CaseStmt>(CurCase->getSubStmt());
1803   }
1804 
1805   // Generate a stop point for debug info if the case statement is
1806   // followed by a default statement. A fallthrough case before a
1807   // default case gets its own branch target.
1808   if (CurCase->getSubStmt()->getStmtClass() == Stmt::DefaultStmtClass)
1809     EmitStopPoint(CurCase);
1810 
1811   // Normal default recursion for non-cases.
1812   EmitStmt(CurCase->getSubStmt());
1813 }
1814 
EmitDefaultStmt(const DefaultStmt & S,ArrayRef<const Attr * > Attrs)1815 void CodeGenFunction::EmitDefaultStmt(const DefaultStmt &S,
1816                                       ArrayRef<const Attr *> Attrs) {
1817   // If there is no enclosing switch instance that we're aware of, then this
1818   // default statement can be elided. This situation only happens when we've
1819   // constant-folded the switch.
1820   if (!SwitchInsn) {
1821     EmitStmt(S.getSubStmt());
1822     return;
1823   }
1824 
1825   llvm::BasicBlock *DefaultBlock = SwitchInsn->getDefaultDest();
1826   assert(DefaultBlock->empty() &&
1827          "EmitDefaultStmt: Default block already defined?");
1828 
1829   if (SwitchLikelihood)
1830     SwitchLikelihood->front() = Stmt::getLikelihood(Attrs);
1831 
1832   EmitBlockWithFallThrough(DefaultBlock, &S);
1833 
1834   EmitStmt(S.getSubStmt());
1835 }
1836 
1837 /// CollectStatementsForCase - Given the body of a 'switch' statement and a
1838 /// constant value that is being switched on, see if we can dead code eliminate
1839 /// the body of the switch to a simple series of statements to emit.  Basically,
1840 /// on a switch (5) we want to find these statements:
1841 ///    case 5:
1842 ///      printf(...);    <--
1843 ///      ++i;            <--
1844 ///      break;
1845 ///
1846 /// and add them to the ResultStmts vector.  If it is unsafe to do this
1847 /// transformation (for example, one of the elided statements contains a label
1848 /// that might be jumped to), return CSFC_Failure.  If we handled it and 'S'
1849 /// should include statements after it (e.g. the printf() line is a substmt of
1850 /// the case) then return CSFC_FallThrough.  If we handled it and found a break
1851 /// statement, then return CSFC_Success.
1852 ///
1853 /// If Case is non-null, then we are looking for the specified case, checking
1854 /// that nothing we jump over contains labels.  If Case is null, then we found
1855 /// the case and are looking for the break.
1856 ///
1857 /// If the recursive walk actually finds our Case, then we set FoundCase to
1858 /// true.
1859 ///
1860 enum CSFC_Result { CSFC_Failure, CSFC_FallThrough, CSFC_Success };
CollectStatementsForCase(const Stmt * S,const SwitchCase * Case,bool & FoundCase,SmallVectorImpl<const Stmt * > & ResultStmts)1861 static CSFC_Result CollectStatementsForCase(const Stmt *S,
1862                                             const SwitchCase *Case,
1863                                             bool &FoundCase,
1864                               SmallVectorImpl<const Stmt*> &ResultStmts) {
1865   // If this is a null statement, just succeed.
1866   if (!S)
1867     return Case ? CSFC_Success : CSFC_FallThrough;
1868 
1869   // If this is the switchcase (case 4: or default) that we're looking for, then
1870   // we're in business.  Just add the substatement.
1871   if (const SwitchCase *SC = dyn_cast<SwitchCase>(S)) {
1872     if (S == Case) {
1873       FoundCase = true;
1874       return CollectStatementsForCase(SC->getSubStmt(), nullptr, FoundCase,
1875                                       ResultStmts);
1876     }
1877 
1878     // Otherwise, this is some other case or default statement, just ignore it.
1879     return CollectStatementsForCase(SC->getSubStmt(), Case, FoundCase,
1880                                     ResultStmts);
1881   }
1882 
1883   // If we are in the live part of the code and we found our break statement,
1884   // return a success!
1885   if (!Case && isa<BreakStmt>(S))
1886     return CSFC_Success;
1887 
1888   // If this is a switch statement, then it might contain the SwitchCase, the
1889   // break, or neither.
1890   if (const CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
1891     // Handle this as two cases: we might be looking for the SwitchCase (if so
1892     // the skipped statements must be skippable) or we might already have it.
1893     CompoundStmt::const_body_iterator I = CS->body_begin(), E = CS->body_end();
1894     bool StartedInLiveCode = FoundCase;
1895     unsigned StartSize = ResultStmts.size();
1896 
1897     // If we've not found the case yet, scan through looking for it.
1898     if (Case) {
1899       // Keep track of whether we see a skipped declaration.  The code could be
1900       // using the declaration even if it is skipped, so we can't optimize out
1901       // the decl if the kept statements might refer to it.
1902       bool HadSkippedDecl = false;
1903 
1904       // If we're looking for the case, just see if we can skip each of the
1905       // substatements.
1906       for (; Case && I != E; ++I) {
1907         HadSkippedDecl |= CodeGenFunction::mightAddDeclToScope(*I);
1908 
1909         switch (CollectStatementsForCase(*I, Case, FoundCase, ResultStmts)) {
1910         case CSFC_Failure: return CSFC_Failure;
1911         case CSFC_Success:
1912           // A successful result means that either 1) that the statement doesn't
1913           // have the case and is skippable, or 2) does contain the case value
1914           // and also contains the break to exit the switch.  In the later case,
1915           // we just verify the rest of the statements are elidable.
1916           if (FoundCase) {
1917             // If we found the case and skipped declarations, we can't do the
1918             // optimization.
1919             if (HadSkippedDecl)
1920               return CSFC_Failure;
1921 
1922             for (++I; I != E; ++I)
1923               if (CodeGenFunction::ContainsLabel(*I, true))
1924                 return CSFC_Failure;
1925             return CSFC_Success;
1926           }
1927           break;
1928         case CSFC_FallThrough:
1929           // If we have a fallthrough condition, then we must have found the
1930           // case started to include statements.  Consider the rest of the
1931           // statements in the compound statement as candidates for inclusion.
1932           assert(FoundCase && "Didn't find case but returned fallthrough?");
1933           // We recursively found Case, so we're not looking for it anymore.
1934           Case = nullptr;
1935 
1936           // If we found the case and skipped declarations, we can't do the
1937           // optimization.
1938           if (HadSkippedDecl)
1939             return CSFC_Failure;
1940           break;
1941         }
1942       }
1943 
1944       if (!FoundCase)
1945         return CSFC_Success;
1946 
1947       assert(!HadSkippedDecl && "fallthrough after skipping decl");
1948     }
1949 
1950     // If we have statements in our range, then we know that the statements are
1951     // live and need to be added to the set of statements we're tracking.
1952     bool AnyDecls = false;
1953     for (; I != E; ++I) {
1954       AnyDecls |= CodeGenFunction::mightAddDeclToScope(*I);
1955 
1956       switch (CollectStatementsForCase(*I, nullptr, FoundCase, ResultStmts)) {
1957       case CSFC_Failure: return CSFC_Failure;
1958       case CSFC_FallThrough:
1959         // A fallthrough result means that the statement was simple and just
1960         // included in ResultStmt, keep adding them afterwards.
1961         break;
1962       case CSFC_Success:
1963         // A successful result means that we found the break statement and
1964         // stopped statement inclusion.  We just ensure that any leftover stmts
1965         // are skippable and return success ourselves.
1966         for (++I; I != E; ++I)
1967           if (CodeGenFunction::ContainsLabel(*I, true))
1968             return CSFC_Failure;
1969         return CSFC_Success;
1970       }
1971     }
1972 
1973     // If we're about to fall out of a scope without hitting a 'break;', we
1974     // can't perform the optimization if there were any decls in that scope
1975     // (we'd lose their end-of-lifetime).
1976     if (AnyDecls) {
1977       // If the entire compound statement was live, there's one more thing we
1978       // can try before giving up: emit the whole thing as a single statement.
1979       // We can do that unless the statement contains a 'break;'.
1980       // FIXME: Such a break must be at the end of a construct within this one.
1981       // We could emit this by just ignoring the BreakStmts entirely.
1982       if (StartedInLiveCode && !CodeGenFunction::containsBreak(S)) {
1983         ResultStmts.resize(StartSize);
1984         ResultStmts.push_back(S);
1985       } else {
1986         return CSFC_Failure;
1987       }
1988     }
1989 
1990     return CSFC_FallThrough;
1991   }
1992 
1993   // Okay, this is some other statement that we don't handle explicitly, like a
1994   // for statement or increment etc.  If we are skipping over this statement,
1995   // just verify it doesn't have labels, which would make it invalid to elide.
1996   if (Case) {
1997     if (CodeGenFunction::ContainsLabel(S, true))
1998       return CSFC_Failure;
1999     return CSFC_Success;
2000   }
2001 
2002   // Otherwise, we want to include this statement.  Everything is cool with that
2003   // so long as it doesn't contain a break out of the switch we're in.
2004   if (CodeGenFunction::containsBreak(S)) return CSFC_Failure;
2005 
2006   // Otherwise, everything is great.  Include the statement and tell the caller
2007   // that we fall through and include the next statement as well.
2008   ResultStmts.push_back(S);
2009   return CSFC_FallThrough;
2010 }
2011 
2012 /// FindCaseStatementsForValue - Find the case statement being jumped to and
2013 /// then invoke CollectStatementsForCase to find the list of statements to emit
2014 /// for a switch on constant.  See the comment above CollectStatementsForCase
2015 /// for more details.
FindCaseStatementsForValue(const SwitchStmt & S,const llvm::APSInt & ConstantCondValue,SmallVectorImpl<const Stmt * > & ResultStmts,ASTContext & C,const SwitchCase * & ResultCase)2016 static bool FindCaseStatementsForValue(const SwitchStmt &S,
2017                                        const llvm::APSInt &ConstantCondValue,
2018                                 SmallVectorImpl<const Stmt*> &ResultStmts,
2019                                        ASTContext &C,
2020                                        const SwitchCase *&ResultCase) {
2021   // First step, find the switch case that is being branched to.  We can do this
2022   // efficiently by scanning the SwitchCase list.
2023   const SwitchCase *Case = S.getSwitchCaseList();
2024   const DefaultStmt *DefaultCase = nullptr;
2025 
2026   for (; Case; Case = Case->getNextSwitchCase()) {
2027     // It's either a default or case.  Just remember the default statement in
2028     // case we're not jumping to any numbered cases.
2029     if (const DefaultStmt *DS = dyn_cast<DefaultStmt>(Case)) {
2030       DefaultCase = DS;
2031       continue;
2032     }
2033 
2034     // Check to see if this case is the one we're looking for.
2035     const CaseStmt *CS = cast<CaseStmt>(Case);
2036     // Don't handle case ranges yet.
2037     if (CS->getRHS()) return false;
2038 
2039     // If we found our case, remember it as 'case'.
2040     if (CS->getLHS()->EvaluateKnownConstInt(C) == ConstantCondValue)
2041       break;
2042   }
2043 
2044   // If we didn't find a matching case, we use a default if it exists, or we
2045   // elide the whole switch body!
2046   if (!Case) {
2047     // It is safe to elide the body of the switch if it doesn't contain labels
2048     // etc.  If it is safe, return successfully with an empty ResultStmts list.
2049     if (!DefaultCase)
2050       return !CodeGenFunction::ContainsLabel(&S);
2051     Case = DefaultCase;
2052   }
2053 
2054   // Ok, we know which case is being jumped to, try to collect all the
2055   // statements that follow it.  This can fail for a variety of reasons.  Also,
2056   // check to see that the recursive walk actually found our case statement.
2057   // Insane cases like this can fail to find it in the recursive walk since we
2058   // don't handle every stmt kind:
2059   // switch (4) {
2060   //   while (1) {
2061   //     case 4: ...
2062   bool FoundCase = false;
2063   ResultCase = Case;
2064   return CollectStatementsForCase(S.getBody(), Case, FoundCase,
2065                                   ResultStmts) != CSFC_Failure &&
2066          FoundCase;
2067 }
2068 
2069 static std::optional<SmallVector<uint64_t, 16>>
getLikelihoodWeights(ArrayRef<Stmt::Likelihood> Likelihoods)2070 getLikelihoodWeights(ArrayRef<Stmt::Likelihood> Likelihoods) {
2071   // Are there enough branches to weight them?
2072   if (Likelihoods.size() <= 1)
2073     return std::nullopt;
2074 
2075   uint64_t NumUnlikely = 0;
2076   uint64_t NumNone = 0;
2077   uint64_t NumLikely = 0;
2078   for (const auto LH : Likelihoods) {
2079     switch (LH) {
2080     case Stmt::LH_Unlikely:
2081       ++NumUnlikely;
2082       break;
2083     case Stmt::LH_None:
2084       ++NumNone;
2085       break;
2086     case Stmt::LH_Likely:
2087       ++NumLikely;
2088       break;
2089     }
2090   }
2091 
2092   // Is there a likelihood attribute used?
2093   if (NumUnlikely == 0 && NumLikely == 0)
2094     return std::nullopt;
2095 
2096   // When multiple cases share the same code they can be combined during
2097   // optimization. In that case the weights of the branch will be the sum of
2098   // the individual weights. Make sure the combined sum of all neutral cases
2099   // doesn't exceed the value of a single likely attribute.
2100   // The additions both avoid divisions by 0 and make sure the weights of None
2101   // don't exceed the weight of Likely.
2102   const uint64_t Likely = INT32_MAX / (NumLikely + 2);
2103   const uint64_t None = Likely / (NumNone + 1);
2104   const uint64_t Unlikely = 0;
2105 
2106   SmallVector<uint64_t, 16> Result;
2107   Result.reserve(Likelihoods.size());
2108   for (const auto LH : Likelihoods) {
2109     switch (LH) {
2110     case Stmt::LH_Unlikely:
2111       Result.push_back(Unlikely);
2112       break;
2113     case Stmt::LH_None:
2114       Result.push_back(None);
2115       break;
2116     case Stmt::LH_Likely:
2117       Result.push_back(Likely);
2118       break;
2119     }
2120   }
2121 
2122   return Result;
2123 }
2124 
EmitSwitchStmt(const SwitchStmt & S)2125 void CodeGenFunction::EmitSwitchStmt(const SwitchStmt &S) {
2126   // Handle nested switch statements.
2127   llvm::SwitchInst *SavedSwitchInsn = SwitchInsn;
2128   SmallVector<uint64_t, 16> *SavedSwitchWeights = SwitchWeights;
2129   SmallVector<Stmt::Likelihood, 16> *SavedSwitchLikelihood = SwitchLikelihood;
2130   llvm::BasicBlock *SavedCRBlock = CaseRangeBlock;
2131 
2132   // See if we can constant fold the condition of the switch and therefore only
2133   // emit the live case statement (if any) of the switch.
2134   llvm::APSInt ConstantCondValue;
2135   if (ConstantFoldsToSimpleInteger(S.getCond(), ConstantCondValue)) {
2136     SmallVector<const Stmt*, 4> CaseStmts;
2137     const SwitchCase *Case = nullptr;
2138     if (FindCaseStatementsForValue(S, ConstantCondValue, CaseStmts,
2139                                    getContext(), Case)) {
2140       if (Case)
2141         incrementProfileCounter(Case);
2142       RunCleanupsScope ExecutedScope(*this);
2143 
2144       if (S.getInit())
2145         EmitStmt(S.getInit());
2146 
2147       // Emit the condition variable if needed inside the entire cleanup scope
2148       // used by this special case for constant folded switches.
2149       if (S.getConditionVariable())
2150         EmitDecl(*S.getConditionVariable());
2151 
2152       // At this point, we are no longer "within" a switch instance, so
2153       // we can temporarily enforce this to ensure that any embedded case
2154       // statements are not emitted.
2155       SwitchInsn = nullptr;
2156 
2157       // Okay, we can dead code eliminate everything except this case.  Emit the
2158       // specified series of statements and we're good.
2159       for (unsigned i = 0, e = CaseStmts.size(); i != e; ++i)
2160         EmitStmt(CaseStmts[i]);
2161       incrementProfileCounter(&S);
2162 
2163       // Now we want to restore the saved switch instance so that nested
2164       // switches continue to function properly
2165       SwitchInsn = SavedSwitchInsn;
2166 
2167       return;
2168     }
2169   }
2170 
2171   JumpDest SwitchExit = getJumpDestInCurrentScope("sw.epilog");
2172 
2173   RunCleanupsScope ConditionScope(*this);
2174 
2175   if (S.getInit())
2176     EmitStmt(S.getInit());
2177 
2178   if (S.getConditionVariable())
2179     EmitDecl(*S.getConditionVariable());
2180   llvm::Value *CondV = EmitScalarExpr(S.getCond());
2181 
2182   // Create basic block to hold stuff that comes after switch
2183   // statement. We also need to create a default block now so that
2184   // explicit case ranges tests can have a place to jump to on
2185   // failure.
2186   llvm::BasicBlock *DefaultBlock = createBasicBlock("sw.default");
2187   SwitchInsn = Builder.CreateSwitch(CondV, DefaultBlock);
2188   if (PGO.haveRegionCounts()) {
2189     // Walk the SwitchCase list to find how many there are.
2190     uint64_t DefaultCount = 0;
2191     unsigned NumCases = 0;
2192     for (const SwitchCase *Case = S.getSwitchCaseList();
2193          Case;
2194          Case = Case->getNextSwitchCase()) {
2195       if (isa<DefaultStmt>(Case))
2196         DefaultCount = getProfileCount(Case);
2197       NumCases += 1;
2198     }
2199     SwitchWeights = new SmallVector<uint64_t, 16>();
2200     SwitchWeights->reserve(NumCases);
2201     // The default needs to be first. We store the edge count, so we already
2202     // know the right weight.
2203     SwitchWeights->push_back(DefaultCount);
2204   } else if (CGM.getCodeGenOpts().OptimizationLevel) {
2205     SwitchLikelihood = new SmallVector<Stmt::Likelihood, 16>();
2206     // Initialize the default case.
2207     SwitchLikelihood->push_back(Stmt::LH_None);
2208   }
2209 
2210   CaseRangeBlock = DefaultBlock;
2211 
2212   // Clear the insertion point to indicate we are in unreachable code.
2213   Builder.ClearInsertionPoint();
2214 
2215   // All break statements jump to NextBlock. If BreakContinueStack is non-empty
2216   // then reuse last ContinueBlock.
2217   JumpDest OuterContinue;
2218   if (!BreakContinueStack.empty())
2219     OuterContinue = BreakContinueStack.back().ContinueBlock;
2220 
2221   BreakContinueStack.push_back(BreakContinue(SwitchExit, OuterContinue));
2222 
2223   // Emit switch body.
2224   EmitStmt(S.getBody());
2225 
2226   BreakContinueStack.pop_back();
2227 
2228   // Update the default block in case explicit case range tests have
2229   // been chained on top.
2230   SwitchInsn->setDefaultDest(CaseRangeBlock);
2231 
2232   // If a default was never emitted:
2233   if (!DefaultBlock->getParent()) {
2234     // If we have cleanups, emit the default block so that there's a
2235     // place to jump through the cleanups from.
2236     if (ConditionScope.requiresCleanups()) {
2237       EmitBlock(DefaultBlock);
2238 
2239     // Otherwise, just forward the default block to the switch end.
2240     } else {
2241       DefaultBlock->replaceAllUsesWith(SwitchExit.getBlock());
2242       delete DefaultBlock;
2243     }
2244   }
2245 
2246   ConditionScope.ForceCleanup();
2247 
2248   // Emit continuation.
2249   EmitBlock(SwitchExit.getBlock(), true);
2250   incrementProfileCounter(&S);
2251 
2252   // If the switch has a condition wrapped by __builtin_unpredictable,
2253   // create metadata that specifies that the switch is unpredictable.
2254   // Don't bother if not optimizing because that metadata would not be used.
2255   auto *Call = dyn_cast<CallExpr>(S.getCond());
2256   if (Call && CGM.getCodeGenOpts().OptimizationLevel != 0) {
2257     auto *FD = dyn_cast_or_null<FunctionDecl>(Call->getCalleeDecl());
2258     if (FD && FD->getBuiltinID() == Builtin::BI__builtin_unpredictable) {
2259       llvm::MDBuilder MDHelper(getLLVMContext());
2260       SwitchInsn->setMetadata(llvm::LLVMContext::MD_unpredictable,
2261                               MDHelper.createUnpredictable());
2262     }
2263   }
2264 
2265   if (SwitchWeights) {
2266     assert(SwitchWeights->size() == 1 + SwitchInsn->getNumCases() &&
2267            "switch weights do not match switch cases");
2268     // If there's only one jump destination there's no sense weighting it.
2269     if (SwitchWeights->size() > 1)
2270       SwitchInsn->setMetadata(llvm::LLVMContext::MD_prof,
2271                               createProfileWeights(*SwitchWeights));
2272     delete SwitchWeights;
2273   } else if (SwitchLikelihood) {
2274     assert(SwitchLikelihood->size() == 1 + SwitchInsn->getNumCases() &&
2275            "switch likelihoods do not match switch cases");
2276     std::optional<SmallVector<uint64_t, 16>> LHW =
2277         getLikelihoodWeights(*SwitchLikelihood);
2278     if (LHW) {
2279       llvm::MDBuilder MDHelper(CGM.getLLVMContext());
2280       SwitchInsn->setMetadata(llvm::LLVMContext::MD_prof,
2281                               createProfileWeights(*LHW));
2282     }
2283     delete SwitchLikelihood;
2284   }
2285   SwitchInsn = SavedSwitchInsn;
2286   SwitchWeights = SavedSwitchWeights;
2287   SwitchLikelihood = SavedSwitchLikelihood;
2288   CaseRangeBlock = SavedCRBlock;
2289 }
2290 
2291 static std::string
SimplifyConstraint(const char * Constraint,const TargetInfo & Target,SmallVectorImpl<TargetInfo::ConstraintInfo> * OutCons=nullptr)2292 SimplifyConstraint(const char *Constraint, const TargetInfo &Target,
2293                  SmallVectorImpl<TargetInfo::ConstraintInfo> *OutCons=nullptr) {
2294   std::string Result;
2295 
2296   while (*Constraint) {
2297     switch (*Constraint) {
2298     default:
2299       Result += Target.convertConstraint(Constraint);
2300       break;
2301     // Ignore these
2302     case '*':
2303     case '?':
2304     case '!':
2305     case '=': // Will see this and the following in mult-alt constraints.
2306     case '+':
2307       break;
2308     case '#': // Ignore the rest of the constraint alternative.
2309       while (Constraint[1] && Constraint[1] != ',')
2310         Constraint++;
2311       break;
2312     case '&':
2313     case '%':
2314       Result += *Constraint;
2315       while (Constraint[1] && Constraint[1] == *Constraint)
2316         Constraint++;
2317       break;
2318     case ',':
2319       Result += "|";
2320       break;
2321     case 'g':
2322       Result += "imr";
2323       break;
2324     case '[': {
2325       assert(OutCons &&
2326              "Must pass output names to constraints with a symbolic name");
2327       unsigned Index;
2328       bool result = Target.resolveSymbolicName(Constraint, *OutCons, Index);
2329       assert(result && "Could not resolve symbolic name"); (void)result;
2330       Result += llvm::utostr(Index);
2331       break;
2332     }
2333     }
2334 
2335     Constraint++;
2336   }
2337 
2338   return Result;
2339 }
2340 
2341 /// AddVariableConstraints - Look at AsmExpr and if it is a variable declared
2342 /// as using a particular register add that as a constraint that will be used
2343 /// in this asm stmt.
2344 static std::string
AddVariableConstraints(const std::string & Constraint,const Expr & AsmExpr,const TargetInfo & Target,CodeGenModule & CGM,const AsmStmt & Stmt,const bool EarlyClobber,std::string * GCCReg=nullptr)2345 AddVariableConstraints(const std::string &Constraint, const Expr &AsmExpr,
2346                        const TargetInfo &Target, CodeGenModule &CGM,
2347                        const AsmStmt &Stmt, const bool EarlyClobber,
2348                        std::string *GCCReg = nullptr) {
2349   const DeclRefExpr *AsmDeclRef = dyn_cast<DeclRefExpr>(&AsmExpr);
2350   if (!AsmDeclRef)
2351     return Constraint;
2352   const ValueDecl &Value = *AsmDeclRef->getDecl();
2353   const VarDecl *Variable = dyn_cast<VarDecl>(&Value);
2354   if (!Variable)
2355     return Constraint;
2356   if (Variable->getStorageClass() != SC_Register)
2357     return Constraint;
2358   AsmLabelAttr *Attr = Variable->getAttr<AsmLabelAttr>();
2359   if (!Attr)
2360     return Constraint;
2361   StringRef Register = Attr->getLabel();
2362   assert(Target.isValidGCCRegisterName(Register));
2363   // We're using validateOutputConstraint here because we only care if
2364   // this is a register constraint.
2365   TargetInfo::ConstraintInfo Info(Constraint, "");
2366   if (Target.validateOutputConstraint(Info) &&
2367       !Info.allowsRegister()) {
2368     CGM.ErrorUnsupported(&Stmt, "__asm__");
2369     return Constraint;
2370   }
2371   // Canonicalize the register here before returning it.
2372   Register = Target.getNormalizedGCCRegisterName(Register);
2373   if (GCCReg != nullptr)
2374     *GCCReg = Register.str();
2375   return (EarlyClobber ? "&{" : "{") + Register.str() + "}";
2376 }
2377 
EmitAsmInputLValue(const TargetInfo::ConstraintInfo & Info,LValue InputValue,QualType InputType,std::string & ConstraintStr,SourceLocation Loc)2378 std::pair<llvm::Value*, llvm::Type *> CodeGenFunction::EmitAsmInputLValue(
2379     const TargetInfo::ConstraintInfo &Info, LValue InputValue,
2380     QualType InputType, std::string &ConstraintStr, SourceLocation Loc) {
2381   if (Info.allowsRegister() || !Info.allowsMemory()) {
2382     if (CodeGenFunction::hasScalarEvaluationKind(InputType))
2383       return {EmitLoadOfLValue(InputValue, Loc).getScalarVal(), nullptr};
2384 
2385     llvm::Type *Ty = ConvertType(InputType);
2386     uint64_t Size = CGM.getDataLayout().getTypeSizeInBits(Ty);
2387     if ((Size <= 64 && llvm::isPowerOf2_64(Size)) ||
2388         getTargetHooks().isScalarizableAsmOperand(*this, Ty)) {
2389       Ty = llvm::IntegerType::get(getLLVMContext(), Size);
2390 
2391       return {Builder.CreateLoad(InputValue.getAddress().withElementType(Ty)),
2392               nullptr};
2393     }
2394   }
2395 
2396   Address Addr = InputValue.getAddress();
2397   ConstraintStr += '*';
2398   return {InputValue.getPointer(*this), Addr.getElementType()};
2399 }
2400 
2401 std::pair<llvm::Value *, llvm::Type *>
EmitAsmInput(const TargetInfo::ConstraintInfo & Info,const Expr * InputExpr,std::string & ConstraintStr)2402 CodeGenFunction::EmitAsmInput(const TargetInfo::ConstraintInfo &Info,
2403                               const Expr *InputExpr,
2404                               std::string &ConstraintStr) {
2405   // If this can't be a register or memory, i.e., has to be a constant
2406   // (immediate or symbolic), try to emit it as such.
2407   if (!Info.allowsRegister() && !Info.allowsMemory()) {
2408     if (Info.requiresImmediateConstant()) {
2409       Expr::EvalResult EVResult;
2410       InputExpr->EvaluateAsRValue(EVResult, getContext(), true);
2411 
2412       llvm::APSInt IntResult;
2413       if (EVResult.Val.toIntegralConstant(IntResult, InputExpr->getType(),
2414                                           getContext()))
2415         return {llvm::ConstantInt::get(getLLVMContext(), IntResult), nullptr};
2416     }
2417 
2418     Expr::EvalResult Result;
2419     if (InputExpr->EvaluateAsInt(Result, getContext()))
2420       return {llvm::ConstantInt::get(getLLVMContext(), Result.Val.getInt()),
2421               nullptr};
2422   }
2423 
2424   if (Info.allowsRegister() || !Info.allowsMemory())
2425     if (CodeGenFunction::hasScalarEvaluationKind(InputExpr->getType()))
2426       return {EmitScalarExpr(InputExpr), nullptr};
2427   if (InputExpr->getStmtClass() == Expr::CXXThisExprClass)
2428     return {EmitScalarExpr(InputExpr), nullptr};
2429   InputExpr = InputExpr->IgnoreParenNoopCasts(getContext());
2430   LValue Dest = EmitLValue(InputExpr);
2431   return EmitAsmInputLValue(Info, Dest, InputExpr->getType(), ConstraintStr,
2432                             InputExpr->getExprLoc());
2433 }
2434 
2435 /// getAsmSrcLocInfo - Return the !srcloc metadata node to attach to an inline
2436 /// asm call instruction.  The !srcloc MDNode contains a list of constant
2437 /// integers which are the source locations of the start of each line in the
2438 /// asm.
getAsmSrcLocInfo(const StringLiteral * Str,CodeGenFunction & CGF)2439 static llvm::MDNode *getAsmSrcLocInfo(const StringLiteral *Str,
2440                                       CodeGenFunction &CGF) {
2441   SmallVector<llvm::Metadata *, 8> Locs;
2442   // Add the location of the first line to the MDNode.
2443   Locs.push_back(llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
2444       CGF.Int64Ty, Str->getBeginLoc().getRawEncoding())));
2445   StringRef StrVal = Str->getString();
2446   if (!StrVal.empty()) {
2447     const SourceManager &SM = CGF.CGM.getContext().getSourceManager();
2448     const LangOptions &LangOpts = CGF.CGM.getLangOpts();
2449     unsigned StartToken = 0;
2450     unsigned ByteOffset = 0;
2451 
2452     // Add the location of the start of each subsequent line of the asm to the
2453     // MDNode.
2454     for (unsigned i = 0, e = StrVal.size() - 1; i != e; ++i) {
2455       if (StrVal[i] != '\n') continue;
2456       SourceLocation LineLoc = Str->getLocationOfByte(
2457           i + 1, SM, LangOpts, CGF.getTarget(), &StartToken, &ByteOffset);
2458       Locs.push_back(llvm::ConstantAsMetadata::get(
2459           llvm::ConstantInt::get(CGF.Int64Ty, LineLoc.getRawEncoding())));
2460     }
2461   }
2462 
2463   return llvm::MDNode::get(CGF.getLLVMContext(), Locs);
2464 }
2465 
UpdateAsmCallInst(llvm::CallBase & Result,bool HasSideEffect,bool HasUnwindClobber,bool ReadOnly,bool ReadNone,bool NoMerge,const AsmStmt & S,const std::vector<llvm::Type * > & ResultRegTypes,const std::vector<llvm::Type * > & ArgElemTypes,CodeGenFunction & CGF,std::vector<llvm::Value * > & RegResults)2466 static void UpdateAsmCallInst(llvm::CallBase &Result, bool HasSideEffect,
2467                               bool HasUnwindClobber, bool ReadOnly,
2468                               bool ReadNone, bool NoMerge, const AsmStmt &S,
2469                               const std::vector<llvm::Type *> &ResultRegTypes,
2470                               const std::vector<llvm::Type *> &ArgElemTypes,
2471                               CodeGenFunction &CGF,
2472                               std::vector<llvm::Value *> &RegResults) {
2473   if (!HasUnwindClobber)
2474     Result.addFnAttr(llvm::Attribute::NoUnwind);
2475 
2476   if (NoMerge)
2477     Result.addFnAttr(llvm::Attribute::NoMerge);
2478   // Attach readnone and readonly attributes.
2479   if (!HasSideEffect) {
2480     if (ReadNone)
2481       Result.setDoesNotAccessMemory();
2482     else if (ReadOnly)
2483       Result.setOnlyReadsMemory();
2484   }
2485 
2486   // Add elementtype attribute for indirect constraints.
2487   for (auto Pair : llvm::enumerate(ArgElemTypes)) {
2488     if (Pair.value()) {
2489       auto Attr = llvm::Attribute::get(
2490           CGF.getLLVMContext(), llvm::Attribute::ElementType, Pair.value());
2491       Result.addParamAttr(Pair.index(), Attr);
2492     }
2493   }
2494 
2495   // Slap the source location of the inline asm into a !srcloc metadata on the
2496   // call.
2497   if (const auto *gccAsmStmt = dyn_cast<GCCAsmStmt>(&S))
2498     Result.setMetadata("srcloc",
2499                        getAsmSrcLocInfo(gccAsmStmt->getAsmString(), CGF));
2500   else {
2501     // At least put the line number on MS inline asm blobs.
2502     llvm::Constant *Loc =
2503         llvm::ConstantInt::get(CGF.Int64Ty, S.getAsmLoc().getRawEncoding());
2504     Result.setMetadata("srcloc",
2505                        llvm::MDNode::get(CGF.getLLVMContext(),
2506                                          llvm::ConstantAsMetadata::get(Loc)));
2507   }
2508 
2509   if (CGF.getLangOpts().assumeFunctionsAreConvergent())
2510     // Conservatively, mark all inline asm blocks in CUDA or OpenCL as
2511     // convergent (meaning, they may call an intrinsically convergent op, such
2512     // as bar.sync, and so can't have certain optimizations applied around
2513     // them).
2514     Result.addFnAttr(llvm::Attribute::Convergent);
2515   // Extract all of the register value results from the asm.
2516   if (ResultRegTypes.size() == 1) {
2517     RegResults.push_back(&Result);
2518   } else {
2519     for (unsigned i = 0, e = ResultRegTypes.size(); i != e; ++i) {
2520       llvm::Value *Tmp = CGF.Builder.CreateExtractValue(&Result, i, "asmresult");
2521       RegResults.push_back(Tmp);
2522     }
2523   }
2524 }
2525 
2526 static void
EmitAsmStores(CodeGenFunction & CGF,const AsmStmt & S,const llvm::ArrayRef<llvm::Value * > RegResults,const llvm::ArrayRef<llvm::Type * > ResultRegTypes,const llvm::ArrayRef<llvm::Type * > ResultTruncRegTypes,const llvm::ArrayRef<LValue> ResultRegDests,const llvm::ArrayRef<QualType> ResultRegQualTys,const llvm::BitVector & ResultTypeRequiresCast,const llvm::BitVector & ResultRegIsFlagReg)2527 EmitAsmStores(CodeGenFunction &CGF, const AsmStmt &S,
2528               const llvm::ArrayRef<llvm::Value *> RegResults,
2529               const llvm::ArrayRef<llvm::Type *> ResultRegTypes,
2530               const llvm::ArrayRef<llvm::Type *> ResultTruncRegTypes,
2531               const llvm::ArrayRef<LValue> ResultRegDests,
2532               const llvm::ArrayRef<QualType> ResultRegQualTys,
2533               const llvm::BitVector &ResultTypeRequiresCast,
2534               const llvm::BitVector &ResultRegIsFlagReg) {
2535   CGBuilderTy &Builder = CGF.Builder;
2536   CodeGenModule &CGM = CGF.CGM;
2537   llvm::LLVMContext &CTX = CGF.getLLVMContext();
2538 
2539   assert(RegResults.size() == ResultRegTypes.size());
2540   assert(RegResults.size() == ResultTruncRegTypes.size());
2541   assert(RegResults.size() == ResultRegDests.size());
2542   // ResultRegDests can be also populated by addReturnRegisterOutputs() above,
2543   // in which case its size may grow.
2544   assert(ResultTypeRequiresCast.size() <= ResultRegDests.size());
2545   assert(ResultRegIsFlagReg.size() <= ResultRegDests.size());
2546 
2547   for (unsigned i = 0, e = RegResults.size(); i != e; ++i) {
2548     llvm::Value *Tmp = RegResults[i];
2549     llvm::Type *TruncTy = ResultTruncRegTypes[i];
2550 
2551     if ((i < ResultRegIsFlagReg.size()) && ResultRegIsFlagReg[i]) {
2552       // Target must guarantee the Value `Tmp` here is lowered to a boolean
2553       // value.
2554       llvm::Constant *Two = llvm::ConstantInt::get(Tmp->getType(), 2);
2555       llvm::Value *IsBooleanValue =
2556           Builder.CreateCmp(llvm::CmpInst::ICMP_ULT, Tmp, Two);
2557       llvm::Function *FnAssume = CGM.getIntrinsic(llvm::Intrinsic::assume);
2558       Builder.CreateCall(FnAssume, IsBooleanValue);
2559     }
2560 
2561     // If the result type of the LLVM IR asm doesn't match the result type of
2562     // the expression, do the conversion.
2563     if (ResultRegTypes[i] != TruncTy) {
2564 
2565       // Truncate the integer result to the right size, note that TruncTy can be
2566       // a pointer.
2567       if (TruncTy->isFloatingPointTy())
2568         Tmp = Builder.CreateFPTrunc(Tmp, TruncTy);
2569       else if (TruncTy->isPointerTy() && Tmp->getType()->isIntegerTy()) {
2570         uint64_t ResSize = CGM.getDataLayout().getTypeSizeInBits(TruncTy);
2571         Tmp = Builder.CreateTrunc(
2572             Tmp, llvm::IntegerType::get(CTX, (unsigned)ResSize));
2573         Tmp = Builder.CreateIntToPtr(Tmp, TruncTy);
2574       } else if (Tmp->getType()->isPointerTy() && TruncTy->isIntegerTy()) {
2575         uint64_t TmpSize =
2576             CGM.getDataLayout().getTypeSizeInBits(Tmp->getType());
2577         Tmp = Builder.CreatePtrToInt(
2578             Tmp, llvm::IntegerType::get(CTX, (unsigned)TmpSize));
2579         Tmp = Builder.CreateTrunc(Tmp, TruncTy);
2580       } else if (Tmp->getType()->isIntegerTy() && TruncTy->isIntegerTy()) {
2581         Tmp = Builder.CreateZExtOrTrunc(Tmp, TruncTy);
2582       } else if (Tmp->getType()->isVectorTy() || TruncTy->isVectorTy()) {
2583         Tmp = Builder.CreateBitCast(Tmp, TruncTy);
2584       }
2585     }
2586 
2587     LValue Dest = ResultRegDests[i];
2588     // ResultTypeRequiresCast elements correspond to the first
2589     // ResultTypeRequiresCast.size() elements of RegResults.
2590     if ((i < ResultTypeRequiresCast.size()) && ResultTypeRequiresCast[i]) {
2591       unsigned Size = CGF.getContext().getTypeSize(ResultRegQualTys[i]);
2592       Address A = Dest.getAddress().withElementType(ResultRegTypes[i]);
2593       if (CGF.getTargetHooks().isScalarizableAsmOperand(CGF, TruncTy)) {
2594         Builder.CreateStore(Tmp, A);
2595         continue;
2596       }
2597 
2598       QualType Ty =
2599           CGF.getContext().getIntTypeForBitwidth(Size, /*Signed=*/false);
2600       if (Ty.isNull()) {
2601         const Expr *OutExpr = S.getOutputExpr(i);
2602         CGM.getDiags().Report(OutExpr->getExprLoc(),
2603                               diag::err_store_value_to_reg);
2604         return;
2605       }
2606       Dest = CGF.MakeAddrLValue(A, Ty);
2607     }
2608     CGF.EmitStoreThroughLValue(RValue::get(Tmp), Dest);
2609   }
2610 }
2611 
EmitHipStdParUnsupportedAsm(CodeGenFunction * CGF,const AsmStmt & S)2612 static void EmitHipStdParUnsupportedAsm(CodeGenFunction *CGF,
2613                                         const AsmStmt &S) {
2614   constexpr auto Name = "__ASM__hipstdpar_unsupported";
2615 
2616   StringRef Asm;
2617   if (auto GCCAsm = dyn_cast<GCCAsmStmt>(&S))
2618     Asm = GCCAsm->getAsmString()->getString();
2619 
2620   auto &Ctx = CGF->CGM.getLLVMContext();
2621 
2622   auto StrTy = llvm::ConstantDataArray::getString(Ctx, Asm);
2623   auto FnTy = llvm::FunctionType::get(llvm::Type::getVoidTy(Ctx),
2624                                       {StrTy->getType()}, false);
2625   auto UBF = CGF->CGM.getModule().getOrInsertFunction(Name, FnTy);
2626 
2627   CGF->Builder.CreateCall(UBF, {StrTy});
2628 }
2629 
EmitAsmStmt(const AsmStmt & S)2630 void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) {
2631   // Pop all cleanup blocks at the end of the asm statement.
2632   CodeGenFunction::RunCleanupsScope Cleanups(*this);
2633 
2634   // Assemble the final asm string.
2635   std::string AsmString = S.generateAsmString(getContext());
2636 
2637   // Get all the output and input constraints together.
2638   SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
2639   SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;
2640 
2641   bool IsHipStdPar = getLangOpts().HIPStdPar && getLangOpts().CUDAIsDevice;
2642   bool IsValidTargetAsm = true;
2643   for (unsigned i = 0, e = S.getNumOutputs(); i != e && IsValidTargetAsm; i++) {
2644     StringRef Name;
2645     if (const GCCAsmStmt *GAS = dyn_cast<GCCAsmStmt>(&S))
2646       Name = GAS->getOutputName(i);
2647     TargetInfo::ConstraintInfo Info(S.getOutputConstraint(i), Name);
2648     bool IsValid = getTarget().validateOutputConstraint(Info); (void)IsValid;
2649     if (IsHipStdPar && !IsValid)
2650       IsValidTargetAsm = false;
2651     else
2652       assert(IsValid && "Failed to parse output constraint");
2653     OutputConstraintInfos.push_back(Info);
2654   }
2655 
2656   for (unsigned i = 0, e = S.getNumInputs(); i != e && IsValidTargetAsm; i++) {
2657     StringRef Name;
2658     if (const GCCAsmStmt *GAS = dyn_cast<GCCAsmStmt>(&S))
2659       Name = GAS->getInputName(i);
2660     TargetInfo::ConstraintInfo Info(S.getInputConstraint(i), Name);
2661     bool IsValid =
2662       getTarget().validateInputConstraint(OutputConstraintInfos, Info);
2663     if (IsHipStdPar && !IsValid)
2664       IsValidTargetAsm = false;
2665     else
2666       assert(IsValid && "Failed to parse input constraint");
2667     InputConstraintInfos.push_back(Info);
2668   }
2669 
2670   if (!IsValidTargetAsm)
2671     return EmitHipStdParUnsupportedAsm(this, S);
2672 
2673   std::string Constraints;
2674 
2675   std::vector<LValue> ResultRegDests;
2676   std::vector<QualType> ResultRegQualTys;
2677   std::vector<llvm::Type *> ResultRegTypes;
2678   std::vector<llvm::Type *> ResultTruncRegTypes;
2679   std::vector<llvm::Type *> ArgTypes;
2680   std::vector<llvm::Type *> ArgElemTypes;
2681   std::vector<llvm::Value*> Args;
2682   llvm::BitVector ResultTypeRequiresCast;
2683   llvm::BitVector ResultRegIsFlagReg;
2684 
2685   // Keep track of inout constraints.
2686   std::string InOutConstraints;
2687   std::vector<llvm::Value*> InOutArgs;
2688   std::vector<llvm::Type*> InOutArgTypes;
2689   std::vector<llvm::Type*> InOutArgElemTypes;
2690 
2691   // Keep track of out constraints for tied input operand.
2692   std::vector<std::string> OutputConstraints;
2693 
2694   // Keep track of defined physregs.
2695   llvm::SmallSet<std::string, 8> PhysRegOutputs;
2696 
2697   // An inline asm can be marked readonly if it meets the following conditions:
2698   //  - it doesn't have any sideeffects
2699   //  - it doesn't clobber memory
2700   //  - it doesn't return a value by-reference
2701   // It can be marked readnone if it doesn't have any input memory constraints
2702   // in addition to meeting the conditions listed above.
2703   bool ReadOnly = true, ReadNone = true;
2704 
2705   for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) {
2706     TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i];
2707 
2708     // Simplify the output constraint.
2709     std::string OutputConstraint(S.getOutputConstraint(i));
2710     OutputConstraint = SimplifyConstraint(OutputConstraint.c_str() + 1,
2711                                           getTarget(), &OutputConstraintInfos);
2712 
2713     const Expr *OutExpr = S.getOutputExpr(i);
2714     OutExpr = OutExpr->IgnoreParenNoopCasts(getContext());
2715 
2716     std::string GCCReg;
2717     OutputConstraint = AddVariableConstraints(OutputConstraint, *OutExpr,
2718                                               getTarget(), CGM, S,
2719                                               Info.earlyClobber(),
2720                                               &GCCReg);
2721     // Give an error on multiple outputs to same physreg.
2722     if (!GCCReg.empty() && !PhysRegOutputs.insert(GCCReg).second)
2723       CGM.Error(S.getAsmLoc(), "multiple outputs to hard register: " + GCCReg);
2724 
2725     OutputConstraints.push_back(OutputConstraint);
2726     LValue Dest = EmitLValue(OutExpr);
2727     if (!Constraints.empty())
2728       Constraints += ',';
2729 
2730     // If this is a register output, then make the inline asm return it
2731     // by-value.  If this is a memory result, return the value by-reference.
2732     QualType QTy = OutExpr->getType();
2733     const bool IsScalarOrAggregate = hasScalarEvaluationKind(QTy) ||
2734                                      hasAggregateEvaluationKind(QTy);
2735     if (!Info.allowsMemory() && IsScalarOrAggregate) {
2736 
2737       Constraints += "=" + OutputConstraint;
2738       ResultRegQualTys.push_back(QTy);
2739       ResultRegDests.push_back(Dest);
2740 
2741       bool IsFlagReg = llvm::StringRef(OutputConstraint).starts_with("{@cc");
2742       ResultRegIsFlagReg.push_back(IsFlagReg);
2743 
2744       llvm::Type *Ty = ConvertTypeForMem(QTy);
2745       const bool RequiresCast = Info.allowsRegister() &&
2746           (getTargetHooks().isScalarizableAsmOperand(*this, Ty) ||
2747            Ty->isAggregateType());
2748 
2749       ResultTruncRegTypes.push_back(Ty);
2750       ResultTypeRequiresCast.push_back(RequiresCast);
2751 
2752       if (RequiresCast) {
2753         unsigned Size = getContext().getTypeSize(QTy);
2754         Ty = llvm::IntegerType::get(getLLVMContext(), Size);
2755       }
2756       ResultRegTypes.push_back(Ty);
2757       // If this output is tied to an input, and if the input is larger, then
2758       // we need to set the actual result type of the inline asm node to be the
2759       // same as the input type.
2760       if (Info.hasMatchingInput()) {
2761         unsigned InputNo;
2762         for (InputNo = 0; InputNo != S.getNumInputs(); ++InputNo) {
2763           TargetInfo::ConstraintInfo &Input = InputConstraintInfos[InputNo];
2764           if (Input.hasTiedOperand() && Input.getTiedOperand() == i)
2765             break;
2766         }
2767         assert(InputNo != S.getNumInputs() && "Didn't find matching input!");
2768 
2769         QualType InputTy = S.getInputExpr(InputNo)->getType();
2770         QualType OutputType = OutExpr->getType();
2771 
2772         uint64_t InputSize = getContext().getTypeSize(InputTy);
2773         if (getContext().getTypeSize(OutputType) < InputSize) {
2774           // Form the asm to return the value as a larger integer or fp type.
2775           ResultRegTypes.back() = ConvertType(InputTy);
2776         }
2777       }
2778       if (llvm::Type* AdjTy =
2779             getTargetHooks().adjustInlineAsmType(*this, OutputConstraint,
2780                                                  ResultRegTypes.back()))
2781         ResultRegTypes.back() = AdjTy;
2782       else {
2783         CGM.getDiags().Report(S.getAsmLoc(),
2784                               diag::err_asm_invalid_type_in_input)
2785             << OutExpr->getType() << OutputConstraint;
2786       }
2787 
2788       // Update largest vector width for any vector types.
2789       if (auto *VT = dyn_cast<llvm::VectorType>(ResultRegTypes.back()))
2790         LargestVectorWidth =
2791             std::max((uint64_t)LargestVectorWidth,
2792                      VT->getPrimitiveSizeInBits().getKnownMinValue());
2793     } else {
2794       Address DestAddr = Dest.getAddress();
2795       // Matrix types in memory are represented by arrays, but accessed through
2796       // vector pointers, with the alignment specified on the access operation.
2797       // For inline assembly, update pointer arguments to use vector pointers.
2798       // Otherwise there will be a mis-match if the matrix is also an
2799       // input-argument which is represented as vector.
2800       if (isa<MatrixType>(OutExpr->getType().getCanonicalType()))
2801         DestAddr = DestAddr.withElementType(ConvertType(OutExpr->getType()));
2802 
2803       ArgTypes.push_back(DestAddr.getType());
2804       ArgElemTypes.push_back(DestAddr.getElementType());
2805       Args.push_back(DestAddr.emitRawPointer(*this));
2806       Constraints += "=*";
2807       Constraints += OutputConstraint;
2808       ReadOnly = ReadNone = false;
2809     }
2810 
2811     if (Info.isReadWrite()) {
2812       InOutConstraints += ',';
2813 
2814       const Expr *InputExpr = S.getOutputExpr(i);
2815       llvm::Value *Arg;
2816       llvm::Type *ArgElemType;
2817       std::tie(Arg, ArgElemType) = EmitAsmInputLValue(
2818           Info, Dest, InputExpr->getType(), InOutConstraints,
2819           InputExpr->getExprLoc());
2820 
2821       if (llvm::Type* AdjTy =
2822           getTargetHooks().adjustInlineAsmType(*this, OutputConstraint,
2823                                                Arg->getType()))
2824         Arg = Builder.CreateBitCast(Arg, AdjTy);
2825 
2826       // Update largest vector width for any vector types.
2827       if (auto *VT = dyn_cast<llvm::VectorType>(Arg->getType()))
2828         LargestVectorWidth =
2829             std::max((uint64_t)LargestVectorWidth,
2830                      VT->getPrimitiveSizeInBits().getKnownMinValue());
2831       // Only tie earlyclobber physregs.
2832       if (Info.allowsRegister() && (GCCReg.empty() || Info.earlyClobber()))
2833         InOutConstraints += llvm::utostr(i);
2834       else
2835         InOutConstraints += OutputConstraint;
2836 
2837       InOutArgTypes.push_back(Arg->getType());
2838       InOutArgElemTypes.push_back(ArgElemType);
2839       InOutArgs.push_back(Arg);
2840     }
2841   }
2842 
2843   // If this is a Microsoft-style asm blob, store the return registers (EAX:EDX)
2844   // to the return value slot. Only do this when returning in registers.
2845   if (isa<MSAsmStmt>(&S)) {
2846     const ABIArgInfo &RetAI = CurFnInfo->getReturnInfo();
2847     if (RetAI.isDirect() || RetAI.isExtend()) {
2848       // Make a fake lvalue for the return value slot.
2849       LValue ReturnSlot = MakeAddrLValueWithoutTBAA(ReturnValue, FnRetTy);
2850       CGM.getTargetCodeGenInfo().addReturnRegisterOutputs(
2851           *this, ReturnSlot, Constraints, ResultRegTypes, ResultTruncRegTypes,
2852           ResultRegDests, AsmString, S.getNumOutputs());
2853       SawAsmBlock = true;
2854     }
2855   }
2856 
2857   for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) {
2858     const Expr *InputExpr = S.getInputExpr(i);
2859 
2860     TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
2861 
2862     if (Info.allowsMemory())
2863       ReadNone = false;
2864 
2865     if (!Constraints.empty())
2866       Constraints += ',';
2867 
2868     // Simplify the input constraint.
2869     std::string InputConstraint(S.getInputConstraint(i));
2870     InputConstraint = SimplifyConstraint(InputConstraint.c_str(), getTarget(),
2871                                          &OutputConstraintInfos);
2872 
2873     InputConstraint = AddVariableConstraints(
2874         InputConstraint, *InputExpr->IgnoreParenNoopCasts(getContext()),
2875         getTarget(), CGM, S, false /* No EarlyClobber */);
2876 
2877     std::string ReplaceConstraint (InputConstraint);
2878     llvm::Value *Arg;
2879     llvm::Type *ArgElemType;
2880     std::tie(Arg, ArgElemType) = EmitAsmInput(Info, InputExpr, Constraints);
2881 
2882     // If this input argument is tied to a larger output result, extend the
2883     // input to be the same size as the output.  The LLVM backend wants to see
2884     // the input and output of a matching constraint be the same size.  Note
2885     // that GCC does not define what the top bits are here.  We use zext because
2886     // that is usually cheaper, but LLVM IR should really get an anyext someday.
2887     if (Info.hasTiedOperand()) {
2888       unsigned Output = Info.getTiedOperand();
2889       QualType OutputType = S.getOutputExpr(Output)->getType();
2890       QualType InputTy = InputExpr->getType();
2891 
2892       if (getContext().getTypeSize(OutputType) >
2893           getContext().getTypeSize(InputTy)) {
2894         // Use ptrtoint as appropriate so that we can do our extension.
2895         if (isa<llvm::PointerType>(Arg->getType()))
2896           Arg = Builder.CreatePtrToInt(Arg, IntPtrTy);
2897         llvm::Type *OutputTy = ConvertType(OutputType);
2898         if (isa<llvm::IntegerType>(OutputTy))
2899           Arg = Builder.CreateZExt(Arg, OutputTy);
2900         else if (isa<llvm::PointerType>(OutputTy))
2901           Arg = Builder.CreateZExt(Arg, IntPtrTy);
2902         else if (OutputTy->isFloatingPointTy())
2903           Arg = Builder.CreateFPExt(Arg, OutputTy);
2904       }
2905       // Deal with the tied operands' constraint code in adjustInlineAsmType.
2906       ReplaceConstraint = OutputConstraints[Output];
2907     }
2908     if (llvm::Type* AdjTy =
2909           getTargetHooks().adjustInlineAsmType(*this, ReplaceConstraint,
2910                                                    Arg->getType()))
2911       Arg = Builder.CreateBitCast(Arg, AdjTy);
2912     else
2913       CGM.getDiags().Report(S.getAsmLoc(), diag::err_asm_invalid_type_in_input)
2914           << InputExpr->getType() << InputConstraint;
2915 
2916     // Update largest vector width for any vector types.
2917     if (auto *VT = dyn_cast<llvm::VectorType>(Arg->getType()))
2918       LargestVectorWidth =
2919           std::max((uint64_t)LargestVectorWidth,
2920                    VT->getPrimitiveSizeInBits().getKnownMinValue());
2921 
2922     ArgTypes.push_back(Arg->getType());
2923     ArgElemTypes.push_back(ArgElemType);
2924     Args.push_back(Arg);
2925     Constraints += InputConstraint;
2926   }
2927 
2928   // Append the "input" part of inout constraints.
2929   for (unsigned i = 0, e = InOutArgs.size(); i != e; i++) {
2930     ArgTypes.push_back(InOutArgTypes[i]);
2931     ArgElemTypes.push_back(InOutArgElemTypes[i]);
2932     Args.push_back(InOutArgs[i]);
2933   }
2934   Constraints += InOutConstraints;
2935 
2936   // Labels
2937   SmallVector<llvm::BasicBlock *, 16> Transfer;
2938   llvm::BasicBlock *Fallthrough = nullptr;
2939   bool IsGCCAsmGoto = false;
2940   if (const auto *GS = dyn_cast<GCCAsmStmt>(&S)) {
2941     IsGCCAsmGoto = GS->isAsmGoto();
2942     if (IsGCCAsmGoto) {
2943       for (const auto *E : GS->labels()) {
2944         JumpDest Dest = getJumpDestForLabel(E->getLabel());
2945         Transfer.push_back(Dest.getBlock());
2946         if (!Constraints.empty())
2947           Constraints += ',';
2948         Constraints += "!i";
2949       }
2950       Fallthrough = createBasicBlock("asm.fallthrough");
2951     }
2952   }
2953 
2954   bool HasUnwindClobber = false;
2955 
2956   // Clobbers
2957   for (unsigned i = 0, e = S.getNumClobbers(); i != e; i++) {
2958     StringRef Clobber = S.getClobber(i);
2959 
2960     if (Clobber == "memory")
2961       ReadOnly = ReadNone = false;
2962     else if (Clobber == "unwind") {
2963       HasUnwindClobber = true;
2964       continue;
2965     } else if (Clobber != "cc") {
2966       Clobber = getTarget().getNormalizedGCCRegisterName(Clobber);
2967       if (CGM.getCodeGenOpts().StackClashProtector &&
2968           getTarget().isSPRegName(Clobber)) {
2969         CGM.getDiags().Report(S.getAsmLoc(),
2970                               diag::warn_stack_clash_protection_inline_asm);
2971       }
2972     }
2973 
2974     if (isa<MSAsmStmt>(&S)) {
2975       if (Clobber == "eax" || Clobber == "edx") {
2976         if (Constraints.find("=&A") != std::string::npos)
2977           continue;
2978         std::string::size_type position1 =
2979             Constraints.find("={" + Clobber.str() + "}");
2980         if (position1 != std::string::npos) {
2981           Constraints.insert(position1 + 1, "&");
2982           continue;
2983         }
2984         std::string::size_type position2 = Constraints.find("=A");
2985         if (position2 != std::string::npos) {
2986           Constraints.insert(position2 + 1, "&");
2987           continue;
2988         }
2989       }
2990     }
2991     if (!Constraints.empty())
2992       Constraints += ',';
2993 
2994     Constraints += "~{";
2995     Constraints += Clobber;
2996     Constraints += '}';
2997   }
2998 
2999   assert(!(HasUnwindClobber && IsGCCAsmGoto) &&
3000          "unwind clobber can't be used with asm goto");
3001 
3002   // Add machine specific clobbers
3003   std::string_view MachineClobbers = getTarget().getClobbers();
3004   if (!MachineClobbers.empty()) {
3005     if (!Constraints.empty())
3006       Constraints += ',';
3007     Constraints += MachineClobbers;
3008   }
3009 
3010   llvm::Type *ResultType;
3011   if (ResultRegTypes.empty())
3012     ResultType = VoidTy;
3013   else if (ResultRegTypes.size() == 1)
3014     ResultType = ResultRegTypes[0];
3015   else
3016     ResultType = llvm::StructType::get(getLLVMContext(), ResultRegTypes);
3017 
3018   llvm::FunctionType *FTy =
3019     llvm::FunctionType::get(ResultType, ArgTypes, false);
3020 
3021   bool HasSideEffect = S.isVolatile() || S.getNumOutputs() == 0;
3022 
3023   llvm::InlineAsm::AsmDialect GnuAsmDialect =
3024       CGM.getCodeGenOpts().getInlineAsmDialect() == CodeGenOptions::IAD_ATT
3025           ? llvm::InlineAsm::AD_ATT
3026           : llvm::InlineAsm::AD_Intel;
3027   llvm::InlineAsm::AsmDialect AsmDialect = isa<MSAsmStmt>(&S) ?
3028     llvm::InlineAsm::AD_Intel : GnuAsmDialect;
3029 
3030   llvm::InlineAsm *IA = llvm::InlineAsm::get(
3031       FTy, AsmString, Constraints, HasSideEffect,
3032       /* IsAlignStack */ false, AsmDialect, HasUnwindClobber);
3033   std::vector<llvm::Value*> RegResults;
3034   llvm::CallBrInst *CBR;
3035   llvm::DenseMap<llvm::BasicBlock *, SmallVector<llvm::Value *, 4>>
3036       CBRRegResults;
3037   if (IsGCCAsmGoto) {
3038     CBR = Builder.CreateCallBr(IA, Fallthrough, Transfer, Args);
3039     EmitBlock(Fallthrough);
3040     UpdateAsmCallInst(*CBR, HasSideEffect, false, ReadOnly, ReadNone,
3041                       InNoMergeAttributedStmt, S, ResultRegTypes, ArgElemTypes,
3042                       *this, RegResults);
3043     // Because we are emitting code top to bottom, we don't have enough
3044     // information at this point to know precisely whether we have a critical
3045     // edge. If we have outputs, split all indirect destinations.
3046     if (!RegResults.empty()) {
3047       unsigned i = 0;
3048       for (llvm::BasicBlock *Dest : CBR->getIndirectDests()) {
3049         llvm::Twine SynthName = Dest->getName() + ".split";
3050         llvm::BasicBlock *SynthBB = createBasicBlock(SynthName);
3051         llvm::IRBuilderBase::InsertPointGuard IPG(Builder);
3052         Builder.SetInsertPoint(SynthBB);
3053 
3054         if (ResultRegTypes.size() == 1) {
3055           CBRRegResults[SynthBB].push_back(CBR);
3056         } else {
3057           for (unsigned j = 0, e = ResultRegTypes.size(); j != e; ++j) {
3058             llvm::Value *Tmp = Builder.CreateExtractValue(CBR, j, "asmresult");
3059             CBRRegResults[SynthBB].push_back(Tmp);
3060           }
3061         }
3062 
3063         EmitBranch(Dest);
3064         EmitBlock(SynthBB);
3065         CBR->setIndirectDest(i++, SynthBB);
3066       }
3067     }
3068   } else if (HasUnwindClobber) {
3069     llvm::CallBase *Result = EmitCallOrInvoke(IA, Args, "");
3070     UpdateAsmCallInst(*Result, HasSideEffect, true, ReadOnly, ReadNone,
3071                       InNoMergeAttributedStmt, S, ResultRegTypes, ArgElemTypes,
3072                       *this, RegResults);
3073   } else {
3074     llvm::CallInst *Result =
3075         Builder.CreateCall(IA, Args, getBundlesForFunclet(IA));
3076     UpdateAsmCallInst(*Result, HasSideEffect, false, ReadOnly, ReadNone,
3077                       InNoMergeAttributedStmt, S, ResultRegTypes, ArgElemTypes,
3078                       *this, RegResults);
3079   }
3080 
3081   EmitAsmStores(*this, S, RegResults, ResultRegTypes, ResultTruncRegTypes,
3082                 ResultRegDests, ResultRegQualTys, ResultTypeRequiresCast,
3083                 ResultRegIsFlagReg);
3084 
3085   // If this is an asm goto with outputs, repeat EmitAsmStores, but with a
3086   // different insertion point; one for each indirect destination and with
3087   // CBRRegResults rather than RegResults.
3088   if (IsGCCAsmGoto && !CBRRegResults.empty()) {
3089     for (llvm::BasicBlock *Succ : CBR->getIndirectDests()) {
3090       llvm::IRBuilderBase::InsertPointGuard IPG(Builder);
3091       Builder.SetInsertPoint(Succ, --(Succ->end()));
3092       EmitAsmStores(*this, S, CBRRegResults[Succ], ResultRegTypes,
3093                     ResultTruncRegTypes, ResultRegDests, ResultRegQualTys,
3094                     ResultTypeRequiresCast, ResultRegIsFlagReg);
3095     }
3096   }
3097 }
3098 
InitCapturedStruct(const CapturedStmt & S)3099 LValue CodeGenFunction::InitCapturedStruct(const CapturedStmt &S) {
3100   const RecordDecl *RD = S.getCapturedRecordDecl();
3101   QualType RecordTy = getContext().getRecordType(RD);
3102 
3103   // Initialize the captured struct.
3104   LValue SlotLV =
3105     MakeAddrLValue(CreateMemTemp(RecordTy, "agg.captured"), RecordTy);
3106 
3107   RecordDecl::field_iterator CurField = RD->field_begin();
3108   for (CapturedStmt::const_capture_init_iterator I = S.capture_init_begin(),
3109                                                  E = S.capture_init_end();
3110        I != E; ++I, ++CurField) {
3111     LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField);
3112     if (CurField->hasCapturedVLAType()) {
3113       EmitLambdaVLACapture(CurField->getCapturedVLAType(), LV);
3114     } else {
3115       EmitInitializerForField(*CurField, LV, *I);
3116     }
3117   }
3118 
3119   return SlotLV;
3120 }
3121 
3122 /// Generate an outlined function for the body of a CapturedStmt, store any
3123 /// captured variables into the captured struct, and call the outlined function.
3124 llvm::Function *
EmitCapturedStmt(const CapturedStmt & S,CapturedRegionKind K)3125 CodeGenFunction::EmitCapturedStmt(const CapturedStmt &S, CapturedRegionKind K) {
3126   LValue CapStruct = InitCapturedStruct(S);
3127 
3128   // Emit the CapturedDecl
3129   CodeGenFunction CGF(CGM, true);
3130   CGCapturedStmtRAII CapInfoRAII(CGF, new CGCapturedStmtInfo(S, K));
3131   llvm::Function *F = CGF.GenerateCapturedStmtFunction(S);
3132   delete CGF.CapturedStmtInfo;
3133 
3134   // Emit call to the helper function.
3135   EmitCallOrInvoke(F, CapStruct.getPointer(*this));
3136 
3137   return F;
3138 }
3139 
GenerateCapturedStmtArgument(const CapturedStmt & S)3140 Address CodeGenFunction::GenerateCapturedStmtArgument(const CapturedStmt &S) {
3141   LValue CapStruct = InitCapturedStruct(S);
3142   return CapStruct.getAddress();
3143 }
3144 
3145 /// Creates the outlined function for a CapturedStmt.
3146 llvm::Function *
GenerateCapturedStmtFunction(const CapturedStmt & S)3147 CodeGenFunction::GenerateCapturedStmtFunction(const CapturedStmt &S) {
3148   assert(CapturedStmtInfo &&
3149     "CapturedStmtInfo should be set when generating the captured function");
3150   const CapturedDecl *CD = S.getCapturedDecl();
3151   const RecordDecl *RD = S.getCapturedRecordDecl();
3152   SourceLocation Loc = S.getBeginLoc();
3153   assert(CD->hasBody() && "missing CapturedDecl body");
3154 
3155   // Build the argument list.
3156   ASTContext &Ctx = CGM.getContext();
3157   FunctionArgList Args;
3158   Args.append(CD->param_begin(), CD->param_end());
3159 
3160   // Create the function declaration.
3161   const CGFunctionInfo &FuncInfo =
3162     CGM.getTypes().arrangeBuiltinFunctionDeclaration(Ctx.VoidTy, Args);
3163   llvm::FunctionType *FuncLLVMTy = CGM.getTypes().GetFunctionType(FuncInfo);
3164 
3165   llvm::Function *F =
3166     llvm::Function::Create(FuncLLVMTy, llvm::GlobalValue::InternalLinkage,
3167                            CapturedStmtInfo->getHelperName(), &CGM.getModule());
3168   CGM.SetInternalFunctionAttributes(CD, F, FuncInfo);
3169   if (CD->isNothrow())
3170     F->addFnAttr(llvm::Attribute::NoUnwind);
3171 
3172   // Generate the function.
3173   StartFunction(CD, Ctx.VoidTy, F, FuncInfo, Args, CD->getLocation(),
3174                 CD->getBody()->getBeginLoc());
3175   // Set the context parameter in CapturedStmtInfo.
3176   Address DeclPtr = GetAddrOfLocalVar(CD->getContextParam());
3177   CapturedStmtInfo->setContextValue(Builder.CreateLoad(DeclPtr));
3178 
3179   // Initialize variable-length arrays.
3180   LValue Base = MakeNaturalAlignRawAddrLValue(
3181       CapturedStmtInfo->getContextValue(), Ctx.getTagDeclType(RD));
3182   for (auto *FD : RD->fields()) {
3183     if (FD->hasCapturedVLAType()) {
3184       auto *ExprArg =
3185           EmitLoadOfLValue(EmitLValueForField(Base, FD), S.getBeginLoc())
3186               .getScalarVal();
3187       auto VAT = FD->getCapturedVLAType();
3188       VLASizeMap[VAT->getSizeExpr()] = ExprArg;
3189     }
3190   }
3191 
3192   // If 'this' is captured, load it into CXXThisValue.
3193   if (CapturedStmtInfo->isCXXThisExprCaptured()) {
3194     FieldDecl *FD = CapturedStmtInfo->getThisFieldDecl();
3195     LValue ThisLValue = EmitLValueForField(Base, FD);
3196     CXXThisValue = EmitLoadOfLValue(ThisLValue, Loc).getScalarVal();
3197   }
3198 
3199   PGO.assignRegionCounters(GlobalDecl(CD), F);
3200   CapturedStmtInfo->EmitBody(*this, CD->getBody());
3201   FinishFunction(CD->getBodyRBrace());
3202 
3203   return F;
3204 }
3205 
3206 namespace {
3207 // Returns the first convergence entry/loop/anchor instruction found in |BB|.
3208 // std::nullptr otherwise.
getConvergenceToken(llvm::BasicBlock * BB)3209 llvm::IntrinsicInst *getConvergenceToken(llvm::BasicBlock *BB) {
3210   for (auto &I : *BB) {
3211     auto *II = dyn_cast<llvm::IntrinsicInst>(&I);
3212     if (II && llvm::isConvergenceControlIntrinsic(II->getIntrinsicID()))
3213       return II;
3214   }
3215   return nullptr;
3216 }
3217 
3218 } // namespace
3219 
3220 llvm::CallBase *
addConvergenceControlToken(llvm::CallBase * Input,llvm::Value * ParentToken)3221 CodeGenFunction::addConvergenceControlToken(llvm::CallBase *Input,
3222                                             llvm::Value *ParentToken) {
3223   llvm::Value *bundleArgs[] = {ParentToken};
3224   llvm::OperandBundleDef OB("convergencectrl", bundleArgs);
3225   auto Output = llvm::CallBase::addOperandBundle(
3226       Input, llvm::LLVMContext::OB_convergencectrl, OB, Input);
3227   Input->replaceAllUsesWith(Output);
3228   Input->eraseFromParent();
3229   return Output;
3230 }
3231 
3232 llvm::IntrinsicInst *
emitConvergenceLoopToken(llvm::BasicBlock * BB,llvm::Value * ParentToken)3233 CodeGenFunction::emitConvergenceLoopToken(llvm::BasicBlock *BB,
3234                                           llvm::Value *ParentToken) {
3235   CGBuilderTy::InsertPoint IP = Builder.saveIP();
3236   if (BB->empty())
3237     Builder.SetInsertPoint(BB);
3238   else
3239     Builder.SetInsertPoint(BB->getFirstInsertionPt());
3240 
3241   llvm::CallBase *CB = Builder.CreateIntrinsic(
3242       llvm::Intrinsic::experimental_convergence_loop, {}, {});
3243   Builder.restoreIP(IP);
3244 
3245   llvm::CallBase *I = addConvergenceControlToken(CB, ParentToken);
3246   return cast<llvm::IntrinsicInst>(I);
3247 }
3248 
3249 llvm::IntrinsicInst *
getOrEmitConvergenceEntryToken(llvm::Function * F)3250 CodeGenFunction::getOrEmitConvergenceEntryToken(llvm::Function *F) {
3251   llvm::BasicBlock *BB = &F->getEntryBlock();
3252   llvm::IntrinsicInst *Token = getConvergenceToken(BB);
3253   if (Token)
3254     return Token;
3255 
3256   // Adding a convergence token requires the function to be marked as
3257   // convergent.
3258   F->setConvergent();
3259 
3260   CGBuilderTy::InsertPoint IP = Builder.saveIP();
3261   Builder.SetInsertPoint(&BB->front());
3262   llvm::CallBase *I = Builder.CreateIntrinsic(
3263       llvm::Intrinsic::experimental_convergence_entry, {}, {});
3264   assert(isa<llvm::IntrinsicInst>(I));
3265   Builder.restoreIP(IP);
3266 
3267   return cast<llvm::IntrinsicInst>(I);
3268 }
3269